I think I can help a little with this!
I went to mainstream school/private school for my GCSEs, where I was a top student and got really good grades. I started struggling with mental health in y10 but school was really supportive and I stayed on for 6th form. I started really struggling mentally then and while we dropped timetable etc as well, I dropped out in December, saying I would take time to get better then start again in September. Making that decision was really hard, thinking about being with the year below and my own year group will go off without me but I came to terms with it.
September came and I was a little bit better but soon dipped again and went back into hospital so missed the 2nd year too and couldn't go back to in person school so started home schooling
Home schooling has been very different. You need to be very diligent, self motivated etc. You don't have anyone telling you how and when to work to keep on top of things. I subscribed to an online platform though I didnt find it that useful, instead I have tutors who do 2hrs per subject per week, like a big lecture then spending the rest of the week writing up notes etc.
Overall I'm now just about to do my exams and go off to uni and the 2yrs missed really don't matter, there's zero need to get caught up in the 'rat race', we have decades of work ahead of us and we aren't all robots that have to do everything at exact same times.
If you had extra time you may be eligible for an EHCP which would help your situation though they're pretty hard to get. Homeschool isn't a magic solution - I used to want it during early secondary but its lonely and mentally tough too. Talk to your parents about it and see about maybe switching to another school for a levels next year or something, start the conversation first and keep options open