if the game can’t even save settings it usually means something is interfering
be it antivirus, read only, folder permission or stuff like Onedrive
C:\Users"user name"\Documents\My Games\Grim Dawn\Settings option.txt
^quick dirty fix can be to just delete the options file and let teh game create a new one (be exited from the game when you do this)
If that doesn’t work it might mean something else is at play, like controlled folder access or antivirus/3rd party security suite where you might need to manually exclude and whitelist grim dawn game folder and save folder
*if there is no folder/file in the above location it’s usually an immediate hint Onedrive has hijacked the folder, which can mean it’s preventing the game from updating it or it’s set to read only etc, in which case you might need to disable ondrive or unlink it entirely from GD’s folder