Is The London Hindering My Progression
So here's what I recommend. Don't listen to what others say about which opening to play. Every play has a different style. If you're liking the London, then go at it! Even grandmasters occasionally play the London from time to time. I suggest learning more endgames or strategy in the middlegames. to get past the 1200-1500 range. My main question is: Do you know proper London theory or only like the setup?
So I know a little bit but it's only like 3 or 4 moves to the main counters like I know enough I can transpose to a queens gambit like setup when it'll win me something trappish on the queenside and how it can end up in the Indian game and stuff like it's not always necessary to castle if your planning a pawn storm on that side up til around move 7 I can blitz out responses with almost no thought maybe 10 moves in my most comfortable lines and it's at worst marginally losing usually
I'm at the point where I'm rarely surprised at an opponents move until middle game but I don't think I've ever been on book past move like 6 my moves are viable but not theory

Don't force yourself. But if you want to play something else, i would suggest you the same setup but with C4.

There's nothing wrong in playing the London for a while. If the goal is improvement, however, I agree that it would be smart to switch things up and leave your comfort zone in order to get familiar with different structures and ideas. Otherwise you might end up like certain "professional chess streamers" who are lost when they see a minority attack or a IQP position because they have been hiding behind the London all their lives.
At rupam I actually prefer the c4 london setup since it's got similar tactics to a queens gambit which is something I messed around with, I find it forces the opponent to make decisions they may not like in the center and keeps my knight tucked in behind my setup
At jenium I know about isolated queens pawn positions because of center trades from the aforementioned c3 london but what's a minority attack

Both of these arguments are complete nonsense. If you remember who said those, just ignore everything those guys tell you.
Meanwhile, be happy that you have an opening. Stop worrying about openings and concentrate on more important stuff. Like tactics, middlegame strategies, endgames, tactics and more tactics.
I know that endgame and middlegame tactics are more important than an opening maybe I should phrase the question better, I was thinking that while I work on my tactics and endgame is there any credence to the thought that a different opening might lead to endgames and middle games with more value for pushing though higher ranks as london seems pretty straight forward to a certain degree. It's a bit of a vague thing I know

The London is a completely respectable and normal opening. It would serve you well even if you were a grandmaster. Changing it won't improve your results. Indeed, it will probably be worse in the short run.
Also, changing your opening just because some guys said something nonsensical - it's just too bizarre.

At jenium I know about isolated queens pawn positions because of center trades from the aforementioned c3 london but what's a minority attack
It was just an example. The minority attack is a typical plan in the Carlsbad pawn structure.
If you're looking for arguments why you shouldn't stick to the London you also might want to look at IM Toth's video. He sums it up pretty well:
https://www.youtube.com/watch?v=Qy-JX7hoy-g&t=125s
Well that's probably the most concise and blunt description of the issues I thought there might be with the london, is there an opening with maybe similar themes so I don't fee like I'm starting again from 0 knowledge. I also like the queens gambit but that's only against d5 which is why I swapped to london


I should say that I prefer open games and always now play 1) e4 with white. That suits name best, but it is a matter of preference and personality, I think