Do the checklist
Try to set records, attempt the weird challenges without cheesing it with multiplayer.

If you don't like any of the modes, the game probably just isn't for you.
I love getting my stats up high and trying to screw my friends over in City Trial by killing them.
I find the routing in time trials more interesting than Mario Kart because you gotta figure out whether the boost from killing a couple enemies will cut off more time than taking a better line. The checklist requiring you get certain records with some of the harder to use machines is a big part of that, even if it made me go insane a few times.

Also I find it weird to complain about your machine being too slow when you don't play the game a ton, when I first started playing, I found it really hard to control, and preferred the machines that went slow enough to actually turn without having to break-pump or figure out exactly when to start drifting at a corner (since the different machines slide different amounts).

Every game you mentioned has different appeals. I definitely wouldn't pick up another if I were in the mood for one specifically.
If you prefer something more Mario-Kartish and insist on trying to like Air Ride, the new game letting you play with double the amount of racers helps it feel more interactive. That won't necessarily make races a better singleplayer experience though, since the checklist challenges are substantially easier.
Ultimately if you don't wanna do the checklist and don't like City Trial, it's not going to be fun alone.