Wait a minute. When Shinigami or any Soul Society dies they reborn in living world. That was the cirlce of life thing, this is why Mayuri Kurotsuchi killed people to make a balance for all three worlds. Quincy King desired to break all three worlds balance to make immortal life possible.
While the only question that was left was about Hollows who died, and the answer was that dead hollow just died. end of story.
that's not how it works, Mayuri killed those souls so that the number of "souls" (humans, hollow and shinigami) can be in balance.
Quincy destroy souls that's why the Shinigami went to war with them so that they can kill them out as they wont need to worry about HM, this also explains why shinigami never went to war with the hollow because they know they cant kill too many of them or they would have to end up killing souls in SS and humans in the living world so they can maintain the balance.
I do agree with you that Kubo retconned what hell was in the first place, now he made it a place where all souls with high enough spiritual pressure will end up going regardless of their evil deeds or not, it kinda of makes it that hell is the true afterlife and if you become strong you will b stuck there for eternity