These new terms have a lot more to do with where people gather on the Internet than anything else. Explains why they’ve shifted so heavily toward visual aspects because their likely first exposure to -punk was seeing cyberpunk or steampunk in film or games and then seeking out community around them hoping to capture some of that mystique for themselves.
Cottagecore is definitely the child of Pinterest x Alt girls wanting to be different when alt went too mainstream to stand out. (Which is kinda punk, but for the wrong reasons.)