I currently daily drive Linux, but in my experience a game being rated as compatible on the Steam Deck doesn't mean it will be compatible with all Linux distros - or even the Steam Deck itself, since a game can be gold rated and then an update can break it and leave an incorrect rating in place for a while. Also, a game being playable doesn't mean that all of its functions will behave as expected.
But all that said I haven't actually run into problems playing anything for a while. For some older games I've even found that the Linux version was inferior to the Windows version via Proton.
There are one type of person in this world. Those that understand arrays, and those that don't.