Related, I've seen a lot of misidentification of Aspie writing as being LLM-generated lately. You seem Aspie to me (and parent does as well) so it makes sense that you'd also see the similarity.
I have a few friends who are definitely at other places on the spectrum and yet not diagnosed. The funny thing is Aspies are the most likely to be diagnosed because their early development can be most obvious, but it's still not always caught. (This is supported by recent research identifying the presence of a finite number of distinct genetic phenotypes in the autistic spectrum.)