Life's too short to waste time doing stuff you don't truly enjoy, if you don't have fun playing with your current team then just leave. No point wasting your time when your goals aren't aligned as everyone else has said.
From the perspective of somebody who spent many many hours playing this game and trying to get better, I never once had to make a decision whether or not to keep playing despite not wanting to. Don't let your thoughts on 'having potential' force you to continue playing, everyone has potential--to become a good player you need to put in a *lot* of time and that may or may not be worth it to you.
Another thing is it's not quite as black and white as it sounds, as you've probably heard: nobody quits tf2. Like any other hobby, there's absolutely no reason to all of a sudden completely stop it forever. Besides doing a few casts and ringing 2 or 3 times, I haven't touched the game for 2 months, and I've found myself a lot happier as a result. I definitely enjoyed playing all these seasons and watching streams and stuff, but sometimes you just have to take a break and focus on real life. But that's not to say I won't come back for LAN's and maybe even play next season or something. Do what's right for you in the moment, if you feel the urge to grind the game and it's not at the sacrifice of other more important things like schoolwork, go for it.