My daughter is / was exactly the same.
Sending much love, as I know how awful it is getting punched, kicked, scratched etc by your child. Mine was also big for her age, she started her periods at 9, and was 5’ 4” when she left primary school.
Her temper was extraordinary, and she could rage for hours .. smashing her room up, throwing things downstairs, just awful. Then I would get in a confrontation with her, that would make the whole thing spiral out of control.
I would sit there crying imaging a future where she was this awful violent adult.
She was also fine in lesson. She started high school and really struggled, she had 2 fights with other girls, and there was 1 incident where she was rude to a teacher (not massive I know).
It was at that point I really started to look at anxiety, I think it’s easy to dismiss it as something trivial, but it isn’t. I also started to send DD to a hypnotherapist, which made a massive difference .. she learned calming strategies, and also why she reacted to things as she did.
The major learning for me was that anxiety is a fear reaction, when the fear reaction kicks in the primitive brain takes over, at this point it becomes about survival, and all that adrenaline kicks in (it’s slightly more complicated). When DD is in this primitive brain mode, there us no point in trying to talk, rationalise with her, shout, be angry .. no point at all, you have to wait for those hormones to dissipate (takes about half an hour) and then you can talk.
As hard as it is (and I have been through that feeling of “I’m a parent they should just do as I say”), but that’s just not the way anxiety works.
So, the hypnotherapy gave us a language to use to talk to each other about how she was feeling, which has been great. I realised that what was important was to keep communication open, that she could talk to me and i wouldn’t judge, that I didn’t belittle how she was feeling, that I was a supporter (if all that makes sense).
She’s 13 now and it’s much much better ... she still has anxiety, but she comes and talks to me about stuff before it gets too much, I pick my battles, I know when to walk away (and come back to it later) - I think part of this is age, along with the hypnotherapy.
We went through a period of refusing to go to school last year (various things will trigger her) and attendance went to 91%, but, this year we ar at 100% .. so fingers crossed.
Anxiety in children is really hard, you will get plenty of people who tell you that your child is just “naughty” and needs some sort of punishment .. learn to smile at these people.