Steam Deck uses Arch Linux w/ KDE desktop. If GW2 isn't on Steam yet by release you can just install Lutris and install GW2 that way, which is what I use. GW2 runs perfectly fine on Linux for me. I haven't noticed much of a performance difference between running it on Windows vs Linux other then having to turn off one graphic setting (I don't have the game open and can't remember which one). I don't know how well the game works with a controller though or if it supports a controller at all. Performance (in general) will be interesting once reviewers get their hands on it.
