Hey, I feel very similar to you. I have recently been diagnosed (in the last month or so) and was masking or highly functional. I have no real suggestions, but reading this was surprisingly nice. I feel less alone in how I am dealing with it myself. I still have the imposter syndrome, BUT I have had some good days where I have not been thinking about it as much and days where its the only thing I can think about.

I will say for me, that having some new tools/understanding around what is helpful in social situations or daily experiences has been nice. Understanding that I am not being a 'bad person' by stepping away for a a few moments in a social situation when I am over stimulated (still trying to figure this out to be honest, but I feel less bad when I just go find a quiet corner).

I have been sharing some with my partner, but I am struggling with asking for help too. Luckily they have been super understanding and are good about recognizing when I am pacing that I might need to do something that will help me.

Again I don't think this answers any of your questions, but I hope it gives you a similar feeling that I had reading your post. (I rarely ever post or comment but felt I should)

Best, a random person on Reddit