I was lucky to have very good professors through most of university (in the US). It makes a huge difference in the experience. I'm sorry you had to deal with all of that, it sounds frustrating as can be. Teachers at any level should be encouraging and helpful, never condescending. I've heard plenty of stories about professors that pretty much power trip over it and use it as a chance to talk down to others, though. It sounds like you've got a lot of them in your area!

Unfortunately I'm not really familiar with the online education space. Khan Academy was what came to mind for me, but mostly only because I've heard it mentioned by others quite a bit. I don't have any personal experience with it or any other sites, so I can't really recommend any specific one to you. I wish you the best of luck in your future education endeavors, though!

I'm also not really any more familiar with quantum computers than you are either. I do remember quantum mechanics being discussed a tiny bit in university, but it was never a focus in any of my classes. It wasn't quantum computers specifically but I recall it being rather focused on statistics; the most specific thing I can remember being probability plots of where a particle might be at any given time (including the possibility that it might tunnel through its container). I never quite grasped it myself, either, but it was never an important part of my coursework so I never really had to.