Xenoblade Chronicles X, and it's not even close for me. A distant number 2 would probably be one of the Assassin's Creed games.
I played a lot of VC on Wii U, mostly in Wii mode (which my Wii U was played in about 75% of the time)
I love Mario Kart 8 on Switch, and have played literally hundreds of hours, but found it somewhat uninteresting on Wii U and I don't think I played it more than 2 or 3.
I describe myself as a little dose of toxic masculinity.