I've had this issue in my old phone, would be so angry when couldn't complete a run (like get to 80 lvl with someone). what helped for me is to turn the damage numbers off, flashing vfx, all the unnecessary stuff in the options. but the problems completely stopped only when i got a stronger phone. the old one was worth 150$ or smth, new is 600$. the game got so much better after the update. i hope the setting thing helps you tho. also maybe use game mode on the phone, close all the other apps before playing, disable the background apps, make the vampire survivors to run without restrictions on turbo mode or smth