I'm not OP, but I'm pretty sure the point is the ritual of it, not the genre itself. Anything will work as long as it's specifically for working, and you don't play the music elsewhere. If you can get a subconscious link in your brain between that music and working, ideally you can be more focused when listening to it.
This is the gist of it. It takes a while for the ritual to sink in. You have to be disciplined about it at first. Eventually it will become second nature.
Now when I want to focus on coding I can throw my playlist on and get a small boost in focus.
The power of association. Our brains seem to be association machines. Smells and sounds to certain memories, times, or places. A ritual helps you deliberately build an unconscious association.
Yeah I totally get that part and I’ve likely done that over the years, but now those same playlists aren’t working for me. They were good while in Uni and first few years of working, but it seems their effects have worn off lol. So I’m always open to finding new obscure niche "focus" playlists or genres. Thank you though!