My understanding is that "aesthetic" is when it's mostly decoration, like house or body. And subculture is when you also *do* things, like the music you listen to or foods you eat or whatever.

I imagine they overlap, and there is probably no way to really tell when someone goes from one to the other (like how much behavior is necessary to be part of the subculture, who knows?)

And you can be part of the subculture without having the visual decoration parts, if you behave certain ways but don't dress the part.