Man, I’ve heard some weird ass stories about Riverdale. Serial killers and magic cults and gay correction church...I think Archie gets mauled by a bear at one point and Jughead is a gang leader...You know, I think this is as close as we're going to get, at least when it comes to anime examples. I remember trying to watch Gantz at one point, only to immediately drop it after the Butter Dog scene. Upon reading your summary, I'm even more glad that I stopped. It sounds like a fucking fever dream.
Oddly, the one example I recently thought of that actually hits all the requirements is not even an anime. It's the show Riverdale.