I'm still early in this game but I remember nebel feeling quite unfinished. After you get Kana to high corruption that's it. Between that point and the ending it's like there's no progression, I'd be happy if this game actually has normal progression lol.
Nebel imo had more varied endings. Progression wise like you said once corruption is high there's really nothing to progress from what I remember. Finishing Nebel felt more satisfying for me because ending was more varied and felt like it mattered more. Two of Nebel's ending is mc becomes a cuck or true love ending. This one it's slut ending, slut ending 2.0, true end platonic relationship, side ending with prince, prince ending. A big part of why the game feels unfinished is the promised stuff that the developers said they would have in the game, but wasn't in the game on release.
Quoting what I said earlier:
"Originally they made it sound like there's gonna be four big areas which was the slums, mansion, brothel, and church. Slums I will say is actually decent and is actually passable with its content. The mansion area as anyone who played the game would say it feels like an actual finished area and wasn't half made. Brothel stuff ended up mostly pixel art content with most of them just repeats of each other. Church one imo is the most disappointing with how they originally made it out to be."
Release of the game ended up having 50% of the content in the mansion and 50% the other three areas. Also form what I've discovered they even cut out some content. You can scroll up and see messages about it.