He then proceeded to nail me to the fucking wall by listing all the strange behaviors he'd observed, including shit I was shit doing while he was talking to me

Holy shit, that's a bit rough.

I'm late diagnosed autistic and ADHD, and whenever I have someone around me realise that they're neurodivergent I always insist that they be gentle with the people around them who are (suddenly) glaringly obviously neurodivergent themselves.

When I'm around undiagnosed neurodivergent people it just so happens that I often share reflections on my own realisations or my own behaviours which are relevant to what's going on for that undiagnosed ND person and they will either say something like "Shit, I do that too..." or they will be silently thinking it in their heads. Obviously I let them work through it on their own time but, to be honest with you, sometimes it takes a lot of effort not to lock eyes with them while deliberately nodding my head up and down slowly.

You have to go easy on people because being late-diagnosed can really feel like the rug is being pulled from under you.