This is easy for me, BotW. I got it for Christmas of 2019 and played around for a couple hours then put it down. Thought the game was fun but wasn't anything I would probably play a ton of.
Then the lockdowns happened in early 2020 and I decided to give the game a real try and was blown away. Just the absolute freedom to tackle any obstacle how I wanted was amazing. I love how you can approach combat situations in so many different ways. Fell in love with the "I wonder what is at the top of this mountain" and just climbing it for the hell of it so I could find the next spot I wanted to get to, lol. Will be one of my favorite forms of entertainment I have ever experienced (perhaps my favorite).
BotW single handily made me a gamer again. I now own several different pieces of BotW memorabilia and preordered my first game (TotK, trying to find the Collector's Edition as well), game console (SE TotK Console), and Amiibo (the new TotK Link).
Nintendo with the Switch: