Upgraded my PC to Win 11 with all kumulative updates.
Also updated Nvidia Driver to current version 527.56 (12/08/2022).
Problem still is the same, although this time the launcher had some "news":
"We've detected a data mismatch, wich may be caused by unsupported mods, corrupt files or unknown data. This could cause crashes or issued running the game. Please see our support page for more information."
So I checked the support page and followed the instructions to clear old patch files and start an integrity check for the files with Steam. The check was fine, all game files are ok.
Additional info: never had any mods installed
I hope Patch 9 will fix the problem, so going on hiatus again
