Oh damn... I have completed it to the point that I have to wait for the new update, and I have forgotten everything... I already dropped it. The only thing I'm certain about is that there is one incomplete quest with an incomplete story with one of the girls (forgot her name, she's one of the professors in a magic school and got our old man mage buddy killed) It may be the same Facility you're talking about, the place where there's gems you need to activate and whatnot, that part is incomplete, you can brute force it and get it done but yeah nothing happens after that part and nothing to do other than collecting the paintings the princess paints for decoration...
Here's a link for all that would help you in your quests
https://www.badkittygames.ca/wiki/index.php?title=Quests
(It's understandable if you feel like you shouldn't click random links, so here's another suggestion: Search up Harem Collector Quest and click the Bad Kitty Games, they're the devs who put that wiki up for players.