Lag issues on IOS

The device I'm currently using is a iPhone 8 plus and each time I travel the world the FPS drop or when I increase the render distance from 8 to 12 since my game is kinda playable. 8 it is the lowest it can go and the maximum is 32 chunks which is very unplayable at this point. Anything above 8 will become unusable. Also when I have it at the lowest setting, I would get random lag spikes when I move around or when the game is saving.