Weird hibernation behavior - works as it should only first time after powering on laptop

Ok, today a had time to test this so I’m reporting back:
I switched kernel as you suggested and first time I tried to hibernate - I got regular black screen with laptop still running on and no internet after logging in again.
I reverted /etc/systemd/sleep.conf to be:

HibernateMode=platform shutdown

and it worked.

Afterwards tried a bunch of times to hibernate/wake up system and only once mentioned in my original post problem occurred.

The thing is this 5.4 kernel gives me also additional problems:

  1. Each time I click “Log Out” button I hear very loud annoying beep sound coming from motherboard, which I can’t turn off.
    (tried this suggestion, but it didn’t do anything)
  2. Each time I hibernate there is this error on the screen:
Summary