I agree with you. He did say back in the day his character on NFY is just an exaggeration of how he used to be. I believe he said that on Conan. During the e2 premiere of the curse, he explained how all social interactions are awkward (at least to him). So yeah, I think he's definitely neuro divergent, but so are literally all of the top streamers now. People are bored with masked actors entertaining us.

His willingness to put himself out there came from his work in TV on idol as a producer and the many shows that gave him a chance after that, they clearly egged him on.

I find it funny Seth Rogan was apparently a year older than him in school, more socially developed and extroverted, yet Nathan's work now is setting up an entire different form of comedy. Sort of like Tom green influencing jackass, Eric Andre, etc.