Having the same problem since i bout my iPhone 12 Pro max day one. Not sure if its an iOS bug or its a hardware issue. Well we can say the hardware and the OS aren’t optimized but thats took too long to be fixed which make me feel thats its just a stutter gate. Im really really frustrated whenever i swipe home it’s randomly stutter like an old cheap phone. Im on 14.4.2 (18D70). I started to feel that apple cant and wont do anything about it, I hope I'm wrong but this is what its seems like so far. I hate it whenever i gi back to my iPhone XS Max i feel like its newer, faster and better in every way. Not to mention force touch 😒. I really regret upgrading from my XS max to the 12PM. 😣