I didn't change any additional settings since I last played a few updates ago. Seems to run pretty good. Though I apologize I don't have what I've adjusted handy to share.
The app works pretty well but the database it has to use isn't as mature/quickly updated as Tv/Movies. I believe it uses musicbrainz? Either way it's not as standard as the others if feels like.
Sorry to hear about your bad experience. The steam deck for me has been a to successful (sorry for the pun) game changer.