Actually, @alex_h - Confirmed: This is the Panel Colorizer
Your log dump confirms this is the exact same Panel Colorizer issue that affected me, not a GPU problem.
Key evidence from your logs:
TypeError: Cannot read property 'cfg' of null
file:///usr/share/plasma/plasmoids/luisbocanegra.panel.colorizer/contents/ui/main.qml
This widget is corrupted and causing your desktop restarts. The Panel Colorizer is trying to access null configuration objects, crashing, then reloading - which explains the “logout/login” behavior without restarting autostart applications.
I don’t think this has anything to do with NVIDIA drivers or Wayland - it’s a broken plasmoid from the recent update that hit at least a few Dr460nized setups.
The timing matches perfectly: your issue started after “that update which broke GRUB” - same update cycle that introduced this Panel Colorizer corruption issue.
Question: Have you tried any of the fixes from this thread about the same issue? https://forum.garudalinux.org/t/plasma-6-4-4-panel-colorizer-causes-plasmashell-crash-dr460nized-theme/45844/26
There were multiple suggestions in there that seemed to bring Dr460nized back before I did my reinstall. My corruption was deep and progressive so I needed to do a fresh install.