Teen Gothic

I'm still quite new here, so please go easy on me…

I've always listened to alternative music, Rock, Metal, Punk etc and more recently I've been listening to goth.

I'm listening to playlists on Spotify called things like "Real goth music" and there's a varied range of styles on there, spanning different decades. What I'm trying to work out is what ties them together and means they are classified as "goth", a lot of them I can't join the dots between, for example there's loads of Joy Division, which sounds nothing like the Sisters of Mercy.

Is it the subject matter, the vocal style, aesthetic of the band or something else, or a mixture of all three? (Or more)

The Cure have always been cited as one of the quintessential goth bands, but what makes songs like "Friday I'm in love" gothic and just not a pop song? Why is "Wasteland" by the mission not just classified as rock.

I'm trying to establish themes in my head, like bass driven melodies, chorus heavy guitars etc but this certainly isn't the rule for everything.

What makes a song goth and not just Rock, Dance, etc? I know it's not just about the aesthetic as there are people who dress in a gothic(ish) style that makes music that isn't considered goth, for example Cradle of Filth, which is probably where I first saw the whole corpse paint, black clothes aesthetic!