There's a new 'cycle' each time you advance to a new floor. Prisoner opinion is increased by having Servants assigned in the dominant roles for the Cuddle Lounge, and Managers make the process even more efficient. But of course, you don't have any Servants to begin with, so if you only do things with captured girls, it's a very slow process. The trick to getting the Summit to work quickly is that, when you finish the first floor, you bring in whichever random people were in your party and you make them into Servants, then kick them out of your party and assign them to the Cuddle Lounge to start training your first new girls.
Bear in mind that Sanctum content is all totally optional and provides minimal gameplay benefit at the moment. Sure, you might be able to get a high-level girl to join your party after enough cuddling, but it's finicky. If you ally with a faction, you can just get miniboss rank girls to join your party directly, skipping most of the need to capture anyone. Aside from that, the recycler can break down unwanted restraints into material for other restraints... but you really won't need the extras if you aren't trying to keep hundreds of prisoners.