I've been exclusively gaming on my Steam Deck since launch and have a slightly different experience. For me, if the game is certified "Playable" or "Verified" on the Steam page, I just download and play it. I have never once tweaked any settings or tried a different version of Proton. I'm sure there are tweaks that can achieve better performance on certain games, but I have never personally felt the need to research that on any game.

For reference, below are my recently played games. All but Trials worked great for me. Trials is marked "Unplayable" on Steam, though I did get it to work for a few hours before it broke.