a few days ago I upgraded my machine (Lenovo ThinkPad T510) from Ubuntu 16.04 to Ubuntu Bionic Beaver, and since then my machine freezes somehow randomly when I use LibreOffice or when I look at pictures using Image Viewer. I would like to point out that these aren't big files or pictures, it freezes with pictures less than 1MB. When it freezes, I can move the mouse, but nothing else, and sometimes I can reboot using REISUB but sometimes not even that. I already performed a memtest86+ and it passed 1 full test with no errors found. Other than that, I don't know what else to do to file a bug for this. How are you supposed to file this type of bugs (random freezes) in Ubuntu? I'd like to point out that I never had these freezes in Ubuntu 16.04 using this same machine. Thanks in advance for your help.

Update #1: I tried executing "tail -n 99 /var/log/Xorg*.log" (with and without sudo), and I get this: "tail: cannot open '/var/log/Xorg*.log' for reading: No such file or directory". Do I need to enable something to get these logs?

Update #2: NOTE:Update removed as I've reached the max amount of characters for the Body of the question.

Update #3: @heynnema here's the result of the commands you suggested:

free -h :

              total        used        free      shared  buff/cache   available
Mem:           7.6G        2.2G        123M        205M        5.3G        4.9G
Swap:          979M         64M        915M

sysctl vm.swappiness :

vm.swappiness = 60

grep -i swap /etc/fstab :

/dev/mapper/ubuntu--vg-swap_1 none            swap    sw              0       0

Update #4: @Raffa, here are the results:

lspci | grep ' VGA '

01:00.0 VGA compatible controller: NVIDIA Corporation GT218M [NVS 3100M] (rev a2)

sudo lshw -C display

  *-display                 
       description: VGA compatible controller
       product: GT218M [NVS 3100M]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:01:00.0
       version: a2
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
       configuration: driver=nouveau latency=0
       resources: irq:31 memory:cc000000-ccffffff memory:d0000000-dfffffff memory:ce000000-cfffffff ioport:2000(size=128) memory:c0000-dffff

apt policy xserver-xorg-input-*

xserver-xorg-input-all:
  Installed: (none)
  Candidate: 1:7.7+19ubuntu7.1
  Version table:
     1:7.7+19ubuntu7.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
     1:7.7+19ubuntu7 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
xserver-xorg-input-synaptics:
  Installed: (none)
  Candidate: 1.9.0-1ubuntu1
  Version table:
     1.9.0-1ubuntu1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-libinput-hwe-18.04:
  Installed: 0.28.1-1~18.04.1
  Candidate: 0.28.1-1~18.04.1
  Version table:
 *** 0.28.1-1~18.04.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        100 /var/lib/dpkg/status
xserver-xorg-input-joystick-hwe-18.04:
  Installed: (none)
  Candidate: 1:1.6.3-1build1~18.04.1
  Version table:
     1:1.6.3-1build1~18.04.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages
xserver-xorg-input-libinput-dev-hwe-18.04:
  Installed: (none)
  Candidate: 0.28.1-1~18.04.1
  Version table:
     0.28.1-1~18.04.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/main i386 Packages
xserver-xorg-input-joystick-dev-hwe-16.04:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-elographics:
  Installed: (none)
  Candidate: 1:1.4.1-1build6
  Version table:
     1:1.4.1-1build6 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-evdev-hwe-16.04-dbg:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-evdev-dev-hwe-16.04:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-aiptek:
  Installed: (none)
  Candidate: 1:1.4.1-2build1
  Version table:
     1:1.4.1-2build1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-wacom-hwe-18.04:
  Installed: 1:0.36.1-0ubuntu1~18.04.1
  Candidate: 1:0.36.1-0ubuntu1~18.04.1
  Version table:
 *** 1:0.36.1-0ubuntu1~18.04.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        100 /var/lib/dpkg/status
xserver-xorg-input-synaptics-dev-hwe-18.04:
  Installed: (none)
  Candidate: 1.9.1-1ubuntu1~18.04.1
  Version table:
     1.9.1-1ubuntu1~18.04.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/universe i386 Packages
xserver-xorg-input-multitouch:
  Installed: (none)
  Candidate: 1.0~rc3-1
  Version table:
     1.0~rc3-1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-void:
  Installed: (none)
  Candidate: 1:1.4.1-1build3
  Version table:
     1:1.4.1-1build3 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-kbd:
  Installed: (none)
  Candidate: 1:1.9.0-1
  Version table:
     1:1.9.0-1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-evdev-hwe-18.04:
  Installed: (none)
  Candidate: 1:2.10.6-1~18.04.1
  Version table:
     1:2.10.6-1~18.04.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages
xserver-xorg-input-evtouch:
  Installed: (none)
  Candidate: (none)
  Version table:
xserver-xorg-input-all-hwe-18.04:
  Installed: 1:7.7+19ubuntu8~18.04.3
  Candidate: 1:7.7+19ubuntu8~18.04.3
  Version table:
 *** 1:7.7+19ubuntu8~18.04.3 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        100 /var/lib/dpkg/status
xserver-xorg-input-libinput:
  Installed: (none)
  Candidate: 0.27.1-1
  Version table:
     0.27.1-1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
xserver-xorg-input-synaptics-hwe-16.04:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-libinput-dev:
  Installed: (none)
  Candidate: 0.27.1-1
  Version table:
     0.27.1-1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
        500 http://mx.archive.ubuntu.com/ubuntu bionic/main i386 Packages
xserver-xorg-input-wacom:
  Installed: (none)
  Candidate: 1:0.36.1-0ubuntu1
  Version table:
     1:0.36.1-0ubuntu1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
xserver-xorg-input-void-hwe-16.04:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-mtrack:
  Installed: (none)
  Candidate: 0.3.1-1build2
  Version table:
     0.3.1-1build2 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-vmmouse:
  Installed: (none)
  Candidate: (none)
  Version table:
xserver-xorg-input-joystick:
  Installed: (none)
  Candidate: 1:1.6.3-1build1
  Version table:
     1:1.6.3-1build1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-joystick-dev-hwe-18.04:
  Installed: (none)
  Candidate: 1:1.6.3-1build1~18.04.1
  Version table:
     1:1.6.3-1build1~18.04.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/universe i386 Packages
xserver-xorg-input-xwiimote:
  Installed: (none)
  Candidate: 0.5-1build3
  Version table:
     0.5-1build3 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-evdev-dev-hwe-18.04:
  Installed: (none)
  Candidate: 1:2.10.6-1~18.04.1
  Version table:
     1:2.10.6-1~18.04.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/universe i386 Packages
xserver-xorg-input-evdev-dbg:
  Installed: (none)
  Candidate: 1:2.10.5-1ubuntu1
  Version table:
     1:2.10.5-1ubuntu1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-evdev-dev:
  Installed: (none)
  Candidate: 1:2.10.5-1ubuntu1
  Version table:
     1:2.10.5-1ubuntu1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe i386 Packages
xserver-xorg-input-libinput-hwe-16.04:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-joystick-hwe-16.04:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-libinput-dev-hwe-16.04:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-evdev:
  Installed: (none)
  Candidate: 1:2.10.5-1ubuntu1
  Version table:
     1:2.10.5-1ubuntu1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-mtrack-hwe-16.04:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-synaptics-hwe-18.04:
  Installed: (none)
  Candidate: 1.9.1-1ubuntu1~18.04.1
  Version table:
     1.9.1-1ubuntu1~18.04.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages
xserver-xorg-input-wacom-hwe-16.04:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-synaptics-dev:
  Installed: (none)
  Candidate: 1.9.0-1ubuntu1
  Version table:
     1.9.0-1ubuntu1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe i386 Packages
xserver-xorg-input-synaptics-dev-hwe-16.04:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-mutouch:
  Installed: (none)
  Candidate: 1:1.3.0-1build9
  Version table:
     1:1.3.0-1build9 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-evdev-hwe-16.04:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-all-hwe-16.04:
  Installed: (none)
  Candidate: 3:14.1
  Version table:
     3:14.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-evdev-hwe-18.04-dbg:
  Installed: (none)
  Candidate: 1:2.10.6-1~18.04.1
  Version table:
     1:2.10.6-1~18.04.1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 Packages
xserver-xorg-input-mouse:
  Installed: (none)
  Candidate: 1:1.9.2-1
  Version table:
     1:1.9.2-1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
xserver-xorg-input-joystick-dev:
  Installed: (none)
  Candidate: 1:1.6.3-1build1
  Version table:
     1:1.6.3-1build1 500
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
        500 http://mx.archive.ubuntu.com/ubuntu bionic/universe i386 Packages

Update #5: @Raffa, I executed the commands you suggested in order to install xserver-xorg-input-all, and rebooted the machine, after which I tested using Image Viewer and LibreOffice Calc, and it froze again, so I rebooted using REISUB. At this point I started to see high CPU usage, but RAM usage remained under 2.5G. First it was slow to transition from pic to pic in Image Viewer, then it froze for about 4 minutes, after that I kept looking at pictures, one video and open a spreadsheet in LibreOffice Calc, it was then when it completely froze. I waited 15 min. approx, and that's when I decided to REISUB.

Update #6: @Raffa, I installed xserver-xorg-input-libinput as suggested, and repeated the test as in Update #5, with same results: the system keeps freezing, high CPU usage, RAM memory remained around 1.7G, and swap memory 0G. I did REISUB to reboot.

Update #7: @Raffa, I'm using a laptop, so the only things connected are the mouse (USB) and the power cord. I rebooted without the mouse, and tested as in Update #5 and #6, with same results, it keeps frezzing, although this time I didn't notice high CPU usage. Here's the output for tail -n 400 /var/log/dpkg.log | grep "status installed" :

2020-04-03 19:03:39 status installed libcilkrts5:amd64 7.5.0-3ubuntu1~18.04
2020-04-03 19:03:39 status installed libubsan0:amd64 7.5.0-3ubuntu1~18.04
2020-04-03 19:03:39 status installed libtsan0:amd64 8.4.0-1ubuntu1~18.04
2020-04-03 19:03:39 status installed linux-libc-dev:amd64 4.15.0-91.92
2020-04-03 19:03:39 status installed liblsan0:amd64 8.4.0-1ubuntu1~18.04
2020-04-03 19:03:39 status installed libmpx2:amd64 8.4.0-1ubuntu1~18.04
2020-04-03 19:03:39 status installed dpkg-dev:all 1.19.0.5ubuntu2.3
2020-04-03 19:03:40 status installed libfakeroot:amd64 1.22-2ubuntu1
2020-04-03 19:03:40 status installed libalgorithm-diff-perl:all 1.19.03-1
2020-04-03 19:03:40 status installed libc-dev-bin:amd64 2.27-3ubuntu1
2020-04-03 19:03:40 status installed manpages-dev:all 4.15-1
2020-04-03 19:03:40 status installed libc6-dev:amd64 2.27-3ubuntu1
2020-04-03 19:03:40 status installed libitm1:amd64 8.4.0-1ubuntu1~18.04
2020-04-03 19:03:40 status installed fakeroot:amd64 1.22-2ubuntu1
2020-04-03 19:03:40 status installed libgcc-7-dev:amd64 7.5.0-3ubuntu1~18.04
2020-04-03 19:03:40 status installed libstdc++-7-dev:amd64 7.5.0-3ubuntu1~18.04
2020-04-03 19:03:40 status installed libalgorithm-merge-perl:all 0.08-3
2020-04-03 19:03:40 status installed libalgorithm-diff-xs-perl:amd64 0.04-5
2020-04-03 19:03:40 status installed gcc-7:amd64 7.5.0-3ubuntu1~18.04
2020-04-03 19:03:40 status installed g++-7:amd64 7.5.0-3ubuntu1~18.04
2020-04-03 19:03:40 status installed gcc:amd64 4:7.4.0-1ubuntu2.3
2020-04-03 19:03:41 status installed g++:amd64 4:7.4.0-1ubuntu2.3
2020-04-03 19:03:41 status installed build-essential:amd64 12.4ubuntu1
2020-04-03 19:03:55 status installed man-db:amd64 2.8.3-2ubuntu0.1
2020-04-03 19:03:56 status installed libc-bin:amd64 2.27-3ubuntu1
2020-04-03 19:29:23 status installed libpugixml1v5:amd64 1.8.1-7
2020-04-03 19:29:23 status installed libwxbase3.0-0v5:amd64 3.0.4+dfsg-3
2020-04-03 19:29:23 status installed filezilla-common:all 3.28.0-1
2020-04-03 19:29:23 status installed libfilezilla0:amd64 0.11.0-1
2020-04-03 19:29:23 status installed libwxgtk3.0-0v5:amd64 3.0.4+dfsg-3
2020-04-03 19:29:23 status installed filezilla:amd64 3.28.0-1
2020-04-03 19:29:23 status installed desktop-file-utils:amd64 0.23-1ubuntu3.18.04.2
2020-04-03 19:29:24 status installed libc-bin:amd64 2.27-3ubuntu1
2020-04-03 19:29:26 status installed man-db:amd64 2.8.3-2ubuntu0.1
2020-04-03 19:29:26 status installed gnome-menus:amd64 3.13.3-11ubuntu1.1
2020-04-03 19:29:26 status installed hicolor-icon-theme:all 0.17-2
2020-04-03 19:29:26 status installed mime-support:all 3.60ubuntu1
2020-04-04 09:13:03 status installed libgd3:amd64 2.2.5-4ubuntu0.4
2020-04-04 09:13:03 status installed libc-bin:amd64 2.27-3ubuntu1
2020-04-04 13:29:59 status installed ubuntu-desktop:amd64 1.417.4
2020-04-04 13:30:00 status installed xorg:amd64 1:7.7+19ubuntu7.1
2020-04-04 13:30:00 status installed xserver-xorg-hwe-18.04:amd64 1:7.7+19ubuntu8~18.04.3
2020-04-04 13:30:00 status installed xserver-xorg-input-all-hwe-18.04:amd64 1:7.7+19ubuntu8~18.04.3
2020-04-04 13:30:01 status installed xserver-xorg-input-all:amd64 1:7.7+19ubuntu7.1
2020-04-04 14:33:29 status installed xserver-xorg-video-all-hwe-18.04:amd64 1:7.7+19ubuntu8~18.04.3
2020-04-04 14:33:29 status installed xserver-xorg-video-vmware-hwe-18.04:amd64 1:13.3.0-2build1~18.04.1
2020-04-04 14:33:29 status installed xserver-xorg-video-amdgpu-hwe-18.04:amd64 19.0.1-1ubuntu1~18.04.1
2020-04-04 14:33:29 status installed xserver-xorg-input-wacom-hwe-18.04:amd64 1:0.36.1-0ubuntu1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-video-vesa-hwe-18.04:amd64 1:2.4.0-1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-video-ati-hwe-18.04:amd64 1:19.0.1-1ubuntu1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-video-radeon-hwe-18.04:amd64 1:19.0.1-1ubuntu1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:30 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:31 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:31 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:31 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:31 status installed xserver-xorg-input-libinput-hwe-18.04:amd64 0.28.1-1~18.04.1
2020-04-04 14:33:31 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:31 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:31 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:31 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:31 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:31 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:32 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:32 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:32 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:32 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:32 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:32 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:32 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:32 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:32 status installed xserver-xorg-core-hwe-18.04:amd64 2:1.20.5+git20191008-0ubuntu1~18.04.1
2020-04-04 14:33:33 status installed xserver-xorg-video-fbdev-hwe-18.04:amd64 1:0.5.0-1ubuntu1~18.04.1
2020-04-04 14:33:33 status installed xserver-xorg-video-intel-hwe-18.04:amd64 2:2.99.917+git20171229-1ubuntu1~18.04.1
2020-04-04 14:33:34 status installed xserver-xorg-video-nouveau-hwe-18.04:amd64 1:1.0.16-1~18.04.1
2020-04-04 14:33:34 status installed xserver-xorg-video-qxl-hwe-18.04:amd64 0.1.5-2build2~18.04.1
2020-04-04 14:33:34 status installed xserver-common:all 2:1.19.6-1ubuntu4.4
2020-04-04 14:33:34 status installed xserver-xorg-core:amd64 2:1.19.6-1ubuntu4.4
2020-04-04 14:33:34 status installed xserver-xorg-input-libinput:amd64 0.27.1-1
2020-04-04 14:33:37 status installed man-db:amd64 2.8.3-2ubuntu0.1
2020-04-04 14:33:37 status installed libc-bin:amd64 2.27-3ubuntu1

Update #8: @Raffa, I did the sudo apt purge nvidia-* and the sudo ubuntu-drivers autoinstall , and so far I haven't experienced any freeze. I repeated the previous test, and more, and it's been working fine. I'll post again if there's any other issue. Thanks a lot for your patience, and advice.