Neurodiversity-affirming preschools for autistic/hyperlexic 3YO

Hello,
Forgive me for a very long post, but I think I have a pretty specific problem and I’m hoping there’s someone out there who has been in my shoes. I am wondering if there is a preschool that would be a just-right fit for my autistic, hyperlexic (and cheerful and active) son, or if I’m letting the perfect be the enemy of the good. 

For him, being hyperlexic means he’s reading (and for the most part understanding) at about a second grade level and he is a gestalt language processor which means he has trouble comprehending/producing spoken language. He’s in speech therapy, OT, and Floortime therapy after school. 

He currently attends a play-based, large preschool and he is relatively content but he’s often on the periphery (e.g. reading a book in a corner during circle time and the like). The teachers have a nice relationship with him but there are too many kids for them to give him a lot of time. And I’m discouraged that he seems to be withdrawing. 

I understand there are smaller schools out there for kids with special needs but behaviorist approaches (ABA, “play-based” ABA, ESDM, NET, PRT) are not what I want for my son and they seem hard to avoid. This is also why I haven’t done the Early Intervention/ IEP process with my school district (OUSD). (Though he has been evaluated and we have the ASD diagnosis for insurance.)

What would be ideal is a smaller school with teachers to encourage him to do more of what he likes. Things like: dramatic readings of “frog and toad,” singing songs in French, jumping on a trampoline and yelling. I want him to grow and be challenged, but only to be more fully himself, not to fit in with other kids. 

Does such a preschool exist? How about elementary school? Am I wrong about getting an IEP and there actually is a scenario with neurodiversity-affirming goals and services through the district? 

It would so appreciate hearing from people who have been through it and managed to avoid behavior-based interventions. And if anyone out there has a hyperlexic kid, I would love to connect! 

Thanks.