There is no linux version. Steam/Valve has been updating their proton versions to work with BG3. I would recommend using their ‘proton experimental.’ If you buy from GOG, you can use Lutris, they have a runner that should install everything needed to run BG3, and it also lists some tweaks to make.
Reddit 2.0…already migrating off this censorship.
You can use LASIM app (Windows/Mac/Linux) to migrate your profile and settings to another instance. Highly recommend.