I have a very similar issue to whelanh and possibly ollilein. I’m using KDE Plasma 6.0.5 on EndeavourOS (arch derivative) with a 3080 and a single Alienware AW3821DW monitor (3840x1600 native res, native G-SYNC) connected via HDMI. Everything was working fine on the 550 driver, after updating to the 555 beta and rebooting the PC my monitor stopped receiving an HDMI signal around about the time wayland should have started (SDDM is set to autologin). I ssh’ed into the PC and ran nvidia-bug-report.sh for this configuration:
nvidia-bug-report-555-aw.log.gz (528.0 KB)
On a hunch based on ollilein’s experience, I switched out the Alienware monitor for an old Dell U2713HM (2560x1440, no g/free-sync) using the same HDMI cable and then got a picture on this monitor straight away. Attached is an nvidia-bug-report.sh with the Dell monitor attached:
nvidia-bug-report-555-dell.log.gz (571.6 KB)
I’ve also just noticed that the KDE display app will only allow me to set the resolution to 1920x1080 on the Dell monitor which is not native res. Edit: this is probably a monitor issue, happens on 550 as well…
Edit 2: Just tried a different HDMI cable with the AW3821DW and no change, still a blank screen. Also tried a Dell S2721DGF (2560x1440p with FreeSync) and it works fine as well.