I'm still working my way through the rest of this discussion so I don't have much to actually say in response to your points here (other than, thank you for articulating them!), but I do want to point you to this fic I wrote a few years ago, which is specifically about how two neurodivergent characters are perceived by the people around them, including by a third ND character--a young woman who is highly concerned with assimilating to normative society, and who offers the main two advice on how better to do so. It's short, and barely a drop in the bucket, but as you mentioned an absence of ND characters who are aware of their divergence from the norm and care about it, I thought it might be worth offering.

https://archiveofourown.org/works/4785884