How to know if my game is running 4k/60

So I have a switch 2 and the game looks nice but I still notice pixelization and the rain looks bad. I have a 4k tv so that shouldn’t be the issue whenever I check the dock settings it says outputting 1080 p so idk. Also when I turn my tv back on while totk is running it says 1080 so I’m not sure anymore. Anyone know how to make it run or not?