There are lots of Switch games that have had to have serious compromises made to run them.
You need to checkout the youtube channel DFRetro that does a thorough analysis of the games between their various console releases.
The switch is slow and old hardware but Nintendo was never going for state of the art and it serves its function well
all of the people were having issues with a patched game (version 1.1) - no idea if it ever got fixed or not, i don't have that game to test. Other than some weirdness on 3rd party games i've never noticed any slowdown on any games i've played.
Mario kart in 4 player mode can only run at 30 fps which looks horrific compared to the 60fps 2 player mode. Most games also seem to suffer from massive load times. Crash team racing and Animal Crossing clock in at literal minutes to load.
Maybe I should try Witcher 3.