I'm completely new to the Switch gaming world, so only played a couple of games, but so far I like best:
Zelda BotW
Metroid Dread
Yoshi is nice too to enjoy with the GF
On the other hand, I just didn't manage to get hooked on Mario Kart (something feels wrong with the gameplay, I just doens't match the fun of Crash Team Racing on PS1 IMHO). Oh and Mario Odissey gives me a nauseous feeling of a Mario 64 where the original naivety was replaced by overabundance of gimmicks. I think I'm just too old and prefer 2D mario.
I actually am looking forward to mod my OLED switch and get Retroarch sweetness on that beautiful screen.