Sonic & All Stars Racing Transformed Collection is a blast if you’re okay with a kart racer.

Flatout 2 is the OG combat racer.

If you’re looking for a true “racing sim” type game I would probably recommend one of the Assetto Corsa games, either the original or competizione.

CarX Drift Racing Online is probably not what you expect, but is really fun. Not exactly a traditional “racing” game because you don’t compete for time, but rather compete for “drift points,” with longer/wider drifts getting more score. It has a surprisingly thorough singleplayer mode, and the multiplayer is relatively relaxed. Multiplayer is setup in an open-world style; you join a big lobby and can just drive around with friends or randoms without actually competing for anything, although people in each lobby can start competitions that everyone else can opt-in to. The main reason I’m recommending it is it has very thorough car customization and is a chill, non-competitive driving game, whether that be singleplayer or multiplayer.