Scream out of a sense of primal angst?
Ahem.
That was probably not helpful, huh?
Come here where others feel my particular flavor of pain, that's what I do.
I also have taken the tactic of walking a seemingly razor-thin margin of 'least-worst' and 'tolerable-- at least sometimes' for solutions to this particular conundrum. We try to hot-house the weakest skills (or at least those which are active impediments to access for the proper level in other domains of strength), in order to gradually nudge the placement into a better place with time.
There is no place for kids like this-- at least not for most people, who live in locations where there really isn't anything suitable for them. That's the bald truth. So all solutions are going to be imperfect.
The short answer is that every solution to this problem is going to be idiosyncratic, because tuning a solution has to take into account the entire child-- as you note, emotional maturity as well as intellectual and physical. DD15 reads as "old" socially and emotionally, so for her, acceleration has been a no-brainer. On the other hand, she's about age-appropriate in terms of executive function (or was, at 13, anyway), and physical development is perhaps a bit behind age, but unevenly so.
It requires being extremely tone-deaf to well-intended advice that doesn't take your WHOLE child into account. I definitely consider the source of such advice or criticism and think carefully about what information they have that I don't-- or vice versa.
