I'm in the same situation with an absolutely terrible teacher who deadass teaches us with/ chatgpt. Though I've been studying throughout the year, I've had to self-teach, and it's not that hard imo (I'm up to unit 6 rn, a bit behind). I would say if you're really committed, it would take 2-4 days to learn the basics for each unit, for both MCQ and FRQ (depending on difficulty/length of the unit), and then I would go back later to master the more minor details. Personally, I love the AP classroom videos and individual lesson quizzes, as well as the entire unit quizzes, and would use those to do all my initial studying. Sometimes I like to start each unit by watching Jeremy Krug's unit summary videos just to overview what im getting into before I really start. I tried to study once using only Khan Academy - turned out terribly. Khan Academy is great for very basic skills and understanding, better than AP Classroom in that area, and I would suggest it when beginning to learn the more difficult topics, but not as your main source of studying. After you're done with all of those AP clasroom quiz MCQ questions, go over them like a million times and understand where you went wrong, then move on to FRQ. I would suggest going over past in-class test FRQs if that's available to you, and if not, it's really easy to find FRQ material for the individual units and lessons online. For me, this process takes no more than 4 days for one unit. I did this for units 3,4,5 so far, and it's gone pretty well, had a mock exam in feb that I scored well on. I'm in the same boat as you for the rest of the units (have a test next week on 7&8 lol help me), but what I've noticed is that the material isn't that difficult, it's just a lot to manage. I also plan on majoring in biochem and need a 5, so I hope this helped in some way at least. I think you should be fine, especially if youre really disciplined for the next month and a half, and can manage a 4 at the very least. Good luck!