

While the game runs natively on the Deck I had frame times jumping all over the place and while the overlay said it runs at 60fps it felt more like 40 or less. No in-game setting got rid of the horrible stutter until I forced steam to use Proton. Once I selected proton the game ran flawlessly at a solid 60fps at medium settings.
Horrible frametimes, fixed by using proton instead of running natively.
the game is really heavy on CPU, you can slightly improve battery life by setting TDM limit to 11 W

lowered FPS
impossible to read, this is a simulator, after all
This game ran way better than I expected, with one exception. Rumble seems to cause the game to slow down (braking, driving offroad). If you turn controller vibration completely off in control settings, the issue goes away.
This is unfortunately also a problem on desktop, and in Project Cars 2 (same engine).
Movement slows down when breaking or other random events making it unplayable (framerate stays locked interestingly enough)