I upgraded my Steamdeck joysticks to a 3rd party with hall effect sensors, the ssd to one with double the capacity, and the fan to one that is silent. There’s people that have upgraded even more things, to the point of using a pcie flat cable to connect a full pcie GPU card.
For racing, you have Fly Dangerous. It is also a successful FOSS game!
https://store.steampowered.com/app/1781750/Fly_Dangerous/