Breath of the Wild, more than 4k hours. I know that dang game by heart in a way that you can show me a random screenshot and I can tell where exactly on the map you're standing.
I'm on my first real playthrough of BOTW and I love it. My wife pretty much exclusively was playing ACNH, and she hasn't touched it since starting BOTW.
Everyone being so hyped about TOTK is really making me want to play BOTW as much as possible, but there is still an itch that can only be scratched by Rocket League, even though the smurfing has gotten worse and worse, and I'm routinely dunked on by 10 years olds.