Black Screen after login / on lock etc

Hi, I have a 4090 GPU and on both drivers 425 and 415 as well as on both Ubuntu 20.04 and 22.04 I experience an issue as follows: I can get to the login screen, or even logged in when the login is set to automatic, but after either logging in in the first case or locking and trying to resume from black screen.
I also attached my nvidia-bug-report.sh if it helps.

nvidia-bug-report.log (3.1 MB)

You also have an amd igpu which is active but doesn’t have a driver, I suspect this might be interfering. Please either disable the igpu in bios or upgrade the kernel using the liquorix ppa and install latest firmware
https://packages.ubuntu.com/en/lunar/linux-firmware

Hmm, so I tried disabling the iGPU but it didn’t seem to help. I also noticed that prime-select was in on-demand mode so tried switching it to nvidia – but when I did this the screen is black on initial log in and not just boot (and not restored when I go back to on demand). I dropped to recovery prompt and ran bug reporter again nad this is what I get - any ideas?

Edit - also in this log it complains about the kernel versions but I get the exact same issue even when booting to the same kernel it was built with - so I don’t think that this is the issue.

nvidia-bug-report.log (2.9 MB)

The log looks like the Xserver and nvidia driver is starting perfectly fine and then is freezing out of the blue without any error message.
Since this is a brand new cpu and mainboard, I guess you need to upgrade to the latest kernel using the liquorix ppa and if even that doesn’t help, check for a bios update for your mainboard.

Tried installing liquorix ppa and also already upgraded my bios the other day to the latest so I don’t think that is an issue… I guess an unsolved mystery for now then :/