I use MegaHack v7 to do things like remove my trail, remove particles, icon hack, FPS counter, etc., and I wanna know if doing this is allowed for speedruns.

Most hacks are not allowed. If you want to look at more rules, take a look at the “game rules”

Fps counter might be allowed since it’s a requirement for pc runs but everything else i don’t think so

FPS counter is ok, if you're talking about " icon bypass " then it should be fine, but if it's a texture pack, then no, and everything else isn't (as far as i'm aware)

Please don’t use any of these mentioned hacks. Use the native Steam FPS counter, not MegaHack’s.