I've just run into the same issue, if not worse. i just upgraded my gpu to a 16gb. ran skyrim special edition on ultra high quality as the test. ran fine for hours. then I try and play Valhiem and it crashes my whole computer right before it hits the start screen. I've tested a couple games now. Seems like Valheim is the only one doing this. No mods, and i've uninstalled and reinstalled twice. perhaps a windows 11 conflict, or a radeon driver conflict? idk.