You know, I hadn't thought about it too much in this context, but I do more or less the same. When I'm around anyone at all, I'm conscious of all my behaviors. The only way I can really turn it off is weed/alcohol, and even then the instinct is just dulled a little, not switched off. I don't think the majority of people are nearly that aware of how each movement or sound they make might be perceived by others. It's largely unconscious for most. And I don't think it's an inherent wiring difference either.
I think growing up different and constantly having it impressed upon you that every single way you're different is wrong takes a toll. Other people are pushing you into a box and demanding you behave this way, not that way. Until you either learn to reject (at least some of) those rules or are pushed so far you burn out and can no longer conform, it's constant stress. And it's so constant that you probably aren't even fully aware of it, particularly if you're also alexithymic and generally have to work harder to identify your emotional state/response to a situation under the best of circumstances.
This leads me to another aspect. If we're viewed as too rigid, then allistics' intrinsic/core selves are perhaps comparatively more malleable. Their core underlying personality is perhaps more ready to adopt the behaviors and beliefs of the group. Quicker to be guided by faith. In which case, perhaps for an allistic person, this pushing and prodding doesn't create this emotional/mental tension in the same way it does when it pushes an autist to mask. Granted, this feels like it's painting an unreasonably broad brush, but maybe there's something to it.
Also, the most solitary jobs I know of are in the tech industry. Otherwise, for really isolated jobs, maybe fire watch or possibly lighthouse work if there are openings. If you have relevant skills, you might be able to work in web design, system administration, or as a programmer ("individual contributor") with minimal public interaction. I'm lucky enough that my managers have more or less recognized that I'm very reluctant to deal directly with customers, so I only have to interact with my small team for the most part. This likely would hurt my ability to progress to higher pay, but certainly avoids certain types of stress, and with the way the last half a decade has gone, I'm only just now reaching a point where I might have energy for that broader social interaction again.
I disagree. I have official diagnoses for both ADHD and ASD and am mostly functional most of the time. If I earned enough, I'd be living on my own. I was diagnosed as an adult within the past few years while working nearly full time and I made it on time to each of the several appointments that went into getting that diagnosis. If what you say is true, I doubt the assessor would have been willing to give a diagnosis.