I promise I am not a reactionary, but I am somewhat uneducated on the subject so I might say something offensive accidentally, sorry in advance about that.
So, does gender dysphoria stem from a disconnect between the body and some "gender socialization" function of the brain, which could be solved by getting socialized and treated by everyone as the correct gender from the start, or something that stems from a disconnect between the brain and the actual body parts and hormones, so the transition is needed to alleviate that, or both?
Yes, nonbinary people can also have bodily "mismatches", for want of a better word. I'm agender and socially I very much don't fit into either the "man" or "woman" category. But my physical transition has looked almost exactly identical to that of a binary trans man, and I'm now comfortable with my body in a way I didn't know was possible before I started transitioning. That being said, I don't always get gendered male by strangers, and I'm glad for it. I like being a little androgynous.
Also, not every nonbinary person is neurodivergent. It's totally possible to be neurotypical and still nonbinary.