I believe the term punk has kind of drifted towards a catch-all term to describe something that clashes against what is considered the norm for most people.
There are definitely traditional punk themes in genres like cyberpunk and solarpunk. I feel like with dieselpunk and steampunk it’s largely a matter aesthetics.
Kind of an easy way to describe broad themes. If you are looking for a game similar to Mad Max for example with a post apocalypse desert that’s full of scavengers it might be easier to just use the term desertpunk.