Honestly, how far out of level does her "leisure" activity suggest that she is, at this point?
I hardly see any point to a single skip if that answer is "many years."
Have you offered to let your DD try a community education class in a topic that interests her? One route into community college classes is to sign up for a side-by-side one (music appreciation, drawing, etc) with a parent for a time or two, just enough to build some credibility that your child belongs in the environment just fine-- and then see if they'll allow her to start soloing, or taking for-credit classes.
Have you investigated virtual schooling? That might allow her to accelerate up to her level without so much worry over possible gaps in a two or three year skip.
It would also remove her from the interpersonal situation which is toxic (no matter what you call it).
My DD was about this age when her existential angst started to truly flower into depression-- they see how ill-fitting the world they live in is, and they also see just how long they will be "waiting" for something better. While 4-8 years doesn't seem like so much TO ME, I'm in my late forties... to a ten year old, that is a very (impossibly, really) long time.
