Ubuntu – Chromium not starting on Ubuntu 20.04

I am running Ubuntu 20.04 x86_64 and using chromium installed with snap:

$ snap list 
Name               Version          Rev   Tracking       Publisher   Notes
chromium           84.0.4147.89     1229  latest/stable  canonical✓  -
core18             20200707         1880  latest/stable  canonical✓  base
gtk-common-themes  0.1-36-gc75f853  1506  latest/stable  canonical✓  -
snapd              2.45.2           8542  latest/stable  canonical✓  snapd

It all seems up-to-date, but chromium can not start. If I launch it, it aborts the execution. In both /var/log/syslog and /var/log/kern.log, the following line is generated:

kernel: [ 1590.847960] traps: chrome[5324] trap int3 ip:557cd4d7b152 sp:7fffde23a9c0 error:0 in chrome[557cd1a59000+7234000]

Also, in /var/log/apport.log, for each execution attempt, this line appears:

ERROR: apport (pid 5556) Thu Jul 16 10:32:47 2020: host pid 5324 crashed in a separate mount namespace, ignoring

What could it be the problem?

Note that the program is chromium, but despite this, the log lines automatically report the name chrome, for reasons I do not know (maybe because chromium is anyway based on chrome).

Update: when launched from a terminal, according to a suggestion in an answer, I get:

$ chromium-browser --disable-extensions
[11036:11036:0716/152514.953429:ERROR:sandbox_linux.cc(374)] InitializeSandbox() called with multiple threads in process gpu-process.
WARNING: Kernel has no file descriptor comparison support: Operation not permitted
Trace/breakpoint trap (core dumped)

With chromium --disable-extensions, the message is the same.

Update 2:

$ chromium-browser --disable-gpu --disable-software-rasterizer
MESA-LOADER: failed to retrieve device information
MESA-LOADER: failed to open i915 (search paths /snap/chromium/1229/usr/lib/x86_64-linux-gnu/dri)
failed to load driver: i915
MESA-LOADER: failed to open kms_swrast (search paths /snap/chromium/1229/usr/lib/x86_64-linux-gnu/dri)
failed to load driver: kms_swrast
MESA-LOADER: failed to open swrast (search paths /snap/chromium/1229/usr/lib/x86_64-linux-gnu/dri)
failed to load swrast driver
Trace/breakpoint trap (core dumped)

and the same with chromium --disable-gpu --disable-software-rasterizer. I did not intentionally install any graphic driver, so I guess I'm using the default ones shipped with Ubuntu 20.04. I use the CPU integrated graphic card, CPU is Intel Core i5 4670.

I also tried to run chromium-browser --disable-gpu --disable-software-rasterizer after export MESA_GLSL_CACHE_DISABLE=true, but the error messages are the same as above.