I can't play my games since moving to a new Mac on MacOS 15.1. GOG GALAXY opes but won't quit and games won't start. I starting to rethink my purchase of Baldur's Gate on Black Friday. Can someone help me please.

I would suggest perhaps a trifle of a question: What prevents you from simply locating the game executable and launching it yourself instead of having your hand held by Galaxy?

For problems related to Galaxy, I suggest asking for help in the dedicated forum section: https://www.gog.com/forum/general_beta_gog_galaxy_2.0

Using GOG Galaxy on anything other than Windows simply sucks. I tried it once and uninstalled it (this was back in the Big Sur era). Is not even an Apple Silicon app.

As gamer on Mac, I would advise you to simply download the standalone installer (it should be just one big file on Mac OS). You may have to uninstall the Galaxy version and transfer the save files.