These don’t exactly “fit in” with the rest of the list, but on Deck I’ve personally had a blast with CarX Drift Racing Online and the Sonic &ASRT Collection

This is already fixed in proton experimental bleeding-edge.

You could probably play the SCS Truck Simulator games basically indefinitely.

Vampire Survivors is an absurdly addicting Deck game, and can be considered grindy if you go for the eggs late-game.

Deep Rock Galactic is a good one too, if you’re okay with no aim assist and playing solo or with randoms.