When you are on Minecraft for the Nintendo switch, the game has a lag spike whenever you open any sort of UI or inventory. It gets even more laggy as you go through the inventory slots, with it being the most laggy on split screen. Steps to reproduce:

1. 1 Create a world (in survival mode).
2. 2 Go through your inventory or a chest, you should experience lots of lag.
3. 3 (optional) Get on split screen and have a player or more open a chest or inventory.
   Related:Minecraft Split Screen Laggy