I echo what previous poster said about open classrooms/sensory overload. Speaking from experience, I can also say how overwhelming they can be to children with any sort of neurodiversity - and that's a lot of us. We'll do fine - maybe exceptionally well - in a well-known quiet environment, but once the rest of the world rushes in we retreat, sometimes very seriously. That is not to say, however, that we don't need to learn to be able to cope. We do. But gently, over time...
This is OUR problem, not for the rest of the world to solve. But it is real. In many cases, we develop some sort of outer case to show 'it's them, not me', and that tends to label us as disruptive and/or insolent, depending on whether we are defiant or conflict -advoidance. Just as an example, my mother was very very good at sewing. When we were small, we would wake up to see that she had created - overnight - a new dress for our favourite doll. We were delighted. That was so kind and loving of her.
Naturally, she began to teach us how to sew. I copied her; I found I was quite good at it. But when I went to the first years of junior school, I was told by - to me - some quite random teacher that I was doing sewing all wrong. (Impartial evidence shows that they were wrong , not me.) I'm afraid that all that teacher taught me - aged 7 or 8 - was to hate school and teacher authority because it did not correspond to the world as I honestly, genuinely experienced it. And I wasn't going to lie about my experience.
Thank goodness, by luck, I ended up as an excellent secondary school. I was a quiet and high performing academic student. The only 'problem' I was ever accused there was of 'insolence'. And that was because I genuinely had not understood why - a trivial and but possibly factual inaccuracy - mattered so much to those in power. Looking back, I must have been hell to teach.
If it matters, I got a place at Oxbridge when I was 17, at a time when 10 men were admitted for every woman and have had a successful career since then.
OP Your child is so young. They can't articulate the sort of feelings that I have described above. Mine might not be theirs, but they might experience similar issues. Perhaps they have bigger problems - I don't know and I can't say.. But perhaps, like me, they simply come from a very lovely, sheltered and rather naive environment. For me and my siblings, that meant that we honestly did not understand how the world out there functioned, and genuinely did not know how to relate it to our home experience, or how anyone might help us how to fit in. I suspect that there are many such cases of - in diagnostic speak - normal; children who still might struggle (depending on their individual needs and vasty differing home environments) in early years school years. Not with the same needs are ours but equally valid ones.