Results on Steam Deck are few and far between with inconsistent results so far. I've seen several people say that they are having a great experience with it and others saying that it is unplayable.
It is technically an unsupported platform for an Early Access game so it's a little tricky to get hard details on it. I think that most people are running in Proton for a better overall experience.
Hopefully you can get some first hand info as I haven't actually tried it myself yet.