I use regularly Lutris, Bottles, ScummVM, Dosbox-X or EmulationStation. So I can play from GOG, Epic, Itch.Io or plain old games (Dos) / emulated.
I do have many titles on Steam as well and generally I don’t look too much at whether something is verified or platinum on ProtonDB, I just avoid titles from companies like Activision, EA, Ubisoft and generally all works very easily or easy enough!
I would recommend to pay a visit to Wipeout Phantom Edition.
It’s an enhanced PC port that uses the original assets from the Playstation CD and I had a lot of fun with it on my deck a few months ago…