It's always been strange to me that Ghost in the Shell is considered cyberpunk. It's about a government agency trying to resolve state-level issues. There are no hard-boiled detectives, no evil corporations, no punk-rock influences, no high-tech low-lifes.
And this isn't unique to Ghost in the Shell either. Lots of classic cyberpunk anime was centered around people working for the government or law enforcement. Appleseed is about a team in the military, Armitage III is about a police officer, Bubblegum Crisis was technically about vigilantes but they worked closely with the police, even modern cyberpunk anime like Psycho Pass centers around a police force. I'll admit Akira starts out with a group of punk biker gangs but it quickly pivots to a story about secret government experiments.
The only thing that really links all those anime to the "cyberpunk" label is the presence of androids and the question of what it means to be human. It doesn't seem to include any of the other aspects of cyberpunk that are typically associated with the more "American" version of cyberpunk. That's not a bad thing by any means, I'm just surprised the Japanese version of cyberpunk didn't end up with its own unique subgenre name since it seems to have evolved from a different set of influences and desires.
And then I discovered Burst City. Burst City was released in 1982 and is heavily influenced by punk-rock culture, to the point that the movie shows entire performances from actual Japanese punk bands. It's an angry, fast-moving, middle-finger to conventional Japanese cinema (with their "cohesive plots" and "story structure").
Any narrative you might expect to find here is pretty thin. If you can say the movie is about anything, it's about a group of punks living in a future dystopian Tokyo who clash with the battle police. And I can see how this movie would fit into the same category as American cyberpunk. It's high-tech low-lifes trying to survive in a dystopian city.
Burst City actually kicked off a small movement of similar movies like Death Powder, Tetsuo: The Iron Man, 964 Pinocchio, and Electric Dragon 80.000V. They're all crazy, kinetic scifi which ignore conventional trends. I'm not saying they're good movies (they're actually pretty hard to watch) but I can see how they fit the "cyberpunk" label more than most "cyberpunk" anime. They are actually punk. If you've never seen any of these movies, I think this video is a good introduction.
Anyway, here's the trailer for Burst City. Of course, being an obscure Japanese movie from the 80s, Burst City isn't streaming anywhere. But also due to being an obscure Japanese movie from the 80s, it's been posted in full to youtube.
I don't think the punk in cyberpunk is referring to punk rock music. Not saying they are mutually exclusive, but you seem to think that they are related.
Also, the main characters don't have to be "low life". GitS is about the characters who are fighting against the punks. The world is cyberpunk.