i really feel i can be a great speedrunner but the ammount of lag in my obs recording i really bad to point it becomes almost unwatchable. will they still accept a run which is unbelievably laggy?

We can't verify a run if the lag is so bad that we can't tell what's going on in the game. I'd suggest trying to tweak some OBS settings to reduce the lag, as there's a lot that can be done by just changing the settings.