I do kind of have a kino, albeit sort of anime-esque, idea to go along with that. Maybe Lucifer inherited God's hell under the idea that the absence of struggle or the absence of evil leads to complacency and decay. Maybe Lucifer decided to inherit the name Satan and allowed himself to be thrown out of heaven and he basically built hell around the idea that if people were bereft of good, would it eventually be sought after or would it be reinvented and the people would sort it out their own way?
It would explain why Hell looks like a cyberpunk city because people from earth came in with their own perceptions of what their idea of a stable lifestyle is, in this case a city, and Lucifer basically allowed his denizens to build it however they wish. It would also fill the gaping plot hole as to why Hell even needs a police force if it's such an evil place. However, in my version, there's a police force because public safety is something people brought down from earth and that was the best way they can enforce it.
Meanwhile, heaven is as the OP described and it's also on the path of decay because now the people there are becoming complacent and apathetic. They are bereft of evil and in this case evil is struggle or suffering. Because none of their paradise is really fought for they start turning to decadent things like what that condescending deer in C.H.E.R.U.B does and maybe they're doing crazy stuff for stimulation or out of sheer boredom.
Just an idea, maybe Lucifer was intentionally portrayed or falsified as evil by the apostles because he's an enemy of god essentially for rebelling. I don't know if these would fit in the overall canon of Helluva Boss or Hazbin, but it would at least justify some of the odd world building choices the shows coming forward with.
