My wife and I are around level 70 now. We aren’t normally very frame rate sensitive. But there are so many mobs on the screen, often including enchanted ones, that, if the frame rate was chugging, I’m sure we would die a lot more than we do now.
I do hope they patch it on the Switch. Because the game keeps cranking more and more mobs, explosions and effects as you level up. I fear it will become harder to enjoy for you 2 as time goes by.