Loy, yes-- ultimately,
all of DD's issue there seem to have been strongly correlated with inappropriate academics. Once she had access to collegiate environs at 14-15, those problems largely disappeared.
Now, I want to also issue the caution that it is also my belief that enduring so many YEARS of what you're describing-- that is, the living in one's own head because the day to day reality around her was unbearable otherwise... and writing "NOTHING" like that-- oy. So familiar.
Well, years and years of that fueled a lot of perfectionism and anxiety issues that formed an underlying vulnerability for even worse things, anxiety-wise.
That part has been VERY rough.
If I had it to do over again, I would have yanked her out of that inappropriate setting SO much sooner. Honestly, I'd have
taken the advice of the local HS counselor when she was 12, and placed her into the local CC, even if it meant that I'd have to escort her and sit with her in class for the first 18 months.
It's only been in the past year or so that DD has finally leveled with me about what on EARTH was going on in her head when she was seemingly so tuned out, avoiding work, etc. etc. She was, to be frank, coping by devising observational/mathematical games with the inputs from the world around her-- and doing a fair amount of dissociating from that world in the process.

If only she'd told us at the time.
All of her work, for many many years, was simply time-filling. Each year, she started with enthusiasm, gleefully dancing around with her brand new textbooks, and then by Halloween, once she'd read them all cover to cover, and peeked through the entire class (as one can do in an online course)-- she
wilted, and began the avoidance again. She finally gave up hoping at about 10-12yo. She no longer expects ANY educational setting to deliver on her fondest hopes there (that she'll spend most of her time learning new things). Not even in college. That makes me sad, but it does save her the disappointment, I guess.
Oh, and another helpful note? I strongly recommend a quarter system for such students-- NOT a semester based one. DD can stand it for 9-10 weeks, but 12 is where her personal breakpoint is for that kind of grind.