I was reading through about to say something and then @BabycakesMatlala said exactly what I was thinking - perfect school behaviour is very much in line with masking habits common in autistic girls. Not that it is necessarily the case but it’s possible - and also that lots of things that work for helping autistic kids can help spirited kids too.
As a former teacher, I can confirm many educators are working with outdated info for ND children, and masking is a habit that actually makes life easier when managing a classroom, so it is rare for it being discussed there. You’ll find some teachers will know more because it’s their own special interest, rather than training delivered to the full teaching staff. (Obviously each school will be different and some will be stellar. And others not.)
Whether is is autistic masking or not, the good bit is she feels safe enough at home to let this energy out. At school she is spending a significant amount of energy on being ‘a good student’ and it may well be depleting her reserve for later. We can’t all be our very best all the time, so our moments of WAHHH come out where we feel safe and secure. The work you’ve already put in must have done a lot here - well done.
Modelling and narrating frustration is probably useful for her. Can you manage to narrate aloud the sort of normal boring frustrations of life, just so she starts to hear how you work it through? Not directing it at her, just saying it so she hears it. Like getting the timings wrong on cooking dinner - ‘Oh, the main is going to be done before the vegetables. Let me see if I can take it out of the oven but put a lid on top to keep it warm and then it won’t burn.’ It will feel a little ridiculous probably!! But just stuff where yep, something is wrong, but no one needs to lose their cool. There’s a way to problem solve. She may really benefit from hearing thought processes like that quite a lot. It won’t be instant, but as it becomes normal to hear, it can become more normal to think.
(On a personal level, I know the other extreme is true - if you live with someone who is always shouting about simple stuff, it is easy to become someone who always shouts about simple stuff! I relearned when I had a uni housemate who was calm as a cucumber.)
Sorry, I’ve written an essay here. You’re doing a great job. Best of luck to you both.