I got you.
Here's some beginner friendly videos that I think might help you.
in the file Apex Rush v1.2 Day\Windows\IslandStuntMap\Saved\Config\Windows, there are a few aditional settings you can change like shading quality and foliage which i couldn't see it the game menu set them to 0 for best performance, resolution scale also gives better performance but can make it look worse, I reccomend 60 or higher if possible