You're thinking of space opera, and I agree the Expanse isn't very 'punk, but it does show the impoverished and those on the fringe of society (ice haulers), as well as corporate power (rent-a-cop detectives). It's like a hard sci-fi version of Game of Thrones, with its ensemble cast of viewpoint characters and otherworldly threat. Perhaps it's more like space post-cyberpunk.
to me the cyberpunk elements in expanse look really like props existing as homage to cyber scifi - they don't have an active role in the movie. It centers on the adventures of the protagonists confronting central power, heads of state and planets etc. blade runner was just a retired policeman pursuing the lowest of the low. very different points of view
The belters are the lowlifes and marginalized of the punk-ish scifi, working in hazardous conditions, and used and discarded by the powers of the universe. I think that's where The Expanse does better. The other more "space adventure" plot points are enjoyable, but more run of the mill.
