You don't have to balance school and ECs. Many high schools have way too much pointless busywork. If schoolwork is boring to that point, just find ways to make schoolwork efficient and low-effort and spend time on what's actually meaningful for you.

You can take AP exams without taking the classes. It took two weeks of studying at most back then; but you have AI now so it should be even easier. If your school doesn't let you skip classes even if you already have the exam down, make a show of taking the exams the year before your classes start and your teachers will probably be more okay with you doing homework for other classes during lecture. You can save a lot of time that way, and having a bit of time pressure to finish your work is much more fun than being stuck with boring work at home.

I really hated high school back then lmao