TM2020 is quite good if you're okay with microtransactions and subscriptions. NIce graphics, runs well on modest hardware, plenty of speed and stunts and a few new track gimmicks that I really do like. I've enjoyed the track designs I've seen so far too. It's quite fun.
If the subscription stuff annoys you but you still want this kind of game, look out for TM2 Stadium on sale - it has a bit less going on overall and is a generation behind graphically, but definitely scratches the TM itch - and as others have mentioned, you can build multi-lap tracks with the included, unhobbled editor. Valley is excellent too, but tbh I don't think anything will ever top TM United Forever.