it would 100% be a hellscape, you're expected to conform entirely and deviations from what's expected socially are frowned upon significantly, it is extremely lonely if you can't be a carbon copy of everyone else. especially if you're a foreigner or have non-asian-looking parents, japanese will never really see you as "japanese", at first they treat you like a tourist but then when that wears off you're seen as below others

it's one of the most conservative cultures on the planet in a lot of ways, perhaps the most conservative in the first world (although it shows it in some weird ways like in respect to the heavy objectification/dismissal/sexualization of women in japanese culture, it doesn't look like "western" sexism a lot of the time). same kind of stuff applies to korea

from an outside perspective, and a tourist's perspective, japan and korea seem like they'd be amazing places to be, beautiful and a lot of fun stuff. but for most people it's just depressing, even for the people living there – great hint as to why the suicide rate is so high, you get practically no support and everything is incredibly superficial

so yeah i would say a pretty awful environment to be in if you're neurodivergent/have a disability in any way, shape, or form, or have any differences that would make you stand out (even so little as being racially different is enough to be ostracized). also the economy is pretty stagnant if you care about that

some people have different experiences, a lot of people love japan, but it's not for a majority of people. but as with anything, if you seriously want to move somewhere you should at least do your research yourself and take a lot of visits beforehand

if you want a "don't bother others" culture you might like finland, it's pretty much like that – i mean they also have an extremely high rate of depression but the culture isn't extremely oppressive like japanese culture is

another suggestion could be eastern europe