Thanks a lot rlkglkejf! That fixed it for me.

For the GOG.com release the file is usually located in /Applications (or where ever you put your gog games).

So try
Code
open /Applications/Baldur\'s\ Gate\ 3.app/Contents/Info.plist

and

Code
codesign --force --deep --sign - /Applications/Baldur\'s\ Gate\ 3.app

I referenced this post in a bug report to GOG and Larian.