Since the price was right and I prefer to avoid Steam when possible, I decided to buy it here and try it out using Wine. So far, I have only started it and moved around a little, but the main game and Before the Storm seem to work just fine. I'm using Wine 5.4 with DXVK enabled. Of course, everyone's system is different, so I can't guarantee anything, but since it didn't require any tweaking aside from the common.dll fix, and it uses the Unreal engine, which usually plays well with Wine, I think it should work for most people.
Note that the fix to the common.dll file described in the "Won't launch: possible FIX" thread is required; it will crash without this change. (GOG might correct this at some point, so after updates, this fix might not be necessary.)