Which settings affect FPS the most?

Hi everyone

Even though I have quite a fast machine, FPS range somewhere between 80-200 fps, depening on where I am in game.

Playing on 1440p ** 144hz ** all ultra/max settings

One thing I would like to keep untouched is the 2.4k render distance.

I would like to get a bit more/more consitant frames. Can someone who has experience with tweeking in H1Z1 tell me what settings do affect the fps most. What would you recommend?

Thanks for your help.