I think Kawasaki def works as a more proper "city between cities" vibe.

Prob not a weighty opinion, but I would probably look around Osaka, the idea of Nishinari mainly. But in general, the mercantile legacy of Osaka just feels more fitting to paint a "anything for a price" kind of dystopia.

And admittedly, I would say a big part of why I think that is that I think the real correct answer is just Ghost in the Shell's Niihama: Borrow heavily from Hong Kong, except it's in Osaka Bay or Tokushima (not sure exactly which, I always thought it was Osaka, but google has turned up both).