I have bad fps, stutters, and horrible hitreg only in competitive, spike, dm and casuals are fine? Is this anticheat ruining my game or what? Does someone know how to fix?

Recently ive encounted a bunch of afkers in my game. They join the game and never play a single second. They just autoclick in spawn so that they could farm EXP to finish the battle pass. You can even surrender because all 5 people need to...