I think most schools have 8 blocks. One is for lunch. One is for study hall, lab, health/gym, etc. Most students would take 5 academic classes (Math, English, Science, History, Language) plus an elective, plus lunch and that free period as noted above.
So, you’ve already got a very rigorous course load. Sounds as if you’re planning on engineering, so your applications probably won’t benefit from taking an online college-level Chinese Literature class. You’ve got a rigorous science, English, Math, social science (Econ), Comp Sci, and Orchestra. I think you are TOTALLY fine with this. The only thing that you could do that might help you get into MIT would be prepping to raise your SAT to stratospheric level, or some incredible engineering research project that would be done/published/win award before February, 2022 (unlikely). As for the other tippy-top schools, if you haven’t done some type of creative, extroverted service project, like organizing your classmates to provide a free “discover the fun of engineering/coding/math” for elementary and middle school students in a nearby poor district for this August or fall, then you might want to consider doing something like that. I don’t know that it would matter for MIT, but it would matter for the Ivies.
Otherwise, I’d consider taking a popular life-skills elective with a good instructor. Something like cooking. Or driver’s ed. You’re definitely going to have enough on your plate with that course load and college applications. I would not go out of your way to take a community college class, unless it’s something that you really want to take, completely aside from buffing your credentials.