I have a feeling Hareta never lost his memory of restarting over and over again, I don't know why I just do. Maybe he HAS chosen all of the heroines atleast once before and the loop continued anyways, or it restarted him because he wasn't truly in love with them, or they're doomed to restart over no matter what, or he's a completionist, idk. I thought about it because of the look he gave Misaki in
Chapter 20 page 11, it looks like a mix of melancholy and adoration. He's probably been trying to romance Misaki for a long time now, and every time he fails he falls more and more in love with him. But that's just a theory