Ubuntu – Ubuntu 18.04 – Dell XPS15 9570 – Impossible to reliably suspend/hibernate

Sadly I decided to upgrade to 18.04. Now I pass half of my work hours fixing bugs.

Today specialty is: suspend the laptop.
Last time I tried to suspend my XPS15 9570 I almost burned up my new 2000$ because it was running for 3 hours in my backpack instead of being suspended.

As well documented in a lot of threads, out of the box 18.04 on a lot of laptop is unable to suspend the laptop. There are official bug reports 3 years old, no solution or fix whatsoever. It will simply wake up after 5 seconds or when you close the lid (very sneaky, very dangerous).

https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1574120
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1786094

I tried everything, the only solution that works for me is the one reported here:

Ubuntu 18.04 – Dell XPS13 9370 no longer suspends on lid close

that is changing the grub config to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash mem_sleep_default=deep"

With this change the system actually suspend properly, but when it wakes up wi-fi/bluetooth adapter are completely dead, not even a reboot is able to bring them back.

Something similar is reported here

https://bugzilla.kernel.org/show_bug.cgi?id=201469

and maybe here
https://bugzilla.redhat.com/show_bug.cgi?id=1514836

I also tried to hibernate, without any success (the system will simply shut down). This is probably my fault since I'm missing a swap partition.

After passing the whole day reading and trying solution I decide to open this thread. My question is simple:
how can I, end user in 2019, suspend my laptop without shutting down wifi or other key components of my HW?

I know that I sound arrogant but I lost one day of work on a standard feature that should not pose any problem.

Thank you for any assistance, I hop you had a better day than mine.