I haven't seen anyone else talk about this prevalent issue, but I'll say my takes on it.
Without a doubt Minecraft on the Nintendo Switch has slow menus. It takes about 30 seconds to load into the starting screen, and if I go to the options menu, it takes about that long when opening it up too. Now this doesn't seem like a huge problem to most of you, but it makes a whole world of difference, especially when you load up a world to play on. Every time I open the start menu to go to my options to change my fov or whatever, I get greeted by 20+ seconds of wait time in between of my input and the games output. And when scrolling through the menu up and down the first five tabs, it already starts to slow down just by moving my cursor.
I just hope more people comment on the things like this because it is really irritating.