You could also attach a keyboard and mouse, though I think that that kind of eliminates the point of the Deck, at least as long as one also has a PC to play on – it might make sense for someone who just uses a Deck and a phone.
In the worst case, i’ll buy a dock and play the FPS games via M/K. I am slowing getting better at slow third person games. Racing and platformers are not an issue. Other than FPS, the Steam Deck is very nice.