Finally, a comment section where most people are agreeing that going out with the manipulative boss is just a bad idea. A woman that just invites you based on you being targeted by other women is just the trash of the trash, totally a catch-22 when the thot is his boss.
Meanwhile, the kouhai seems the only logical choice since he has no feelings for Sayu yet (hardly think they will stay forever made up family when she is the heroine of the story), and he would never date her while being underage.
I saw the Anime adaptation news yesterday on r/anime and I think it will be a tier B anime. The first 3 episodes will be great but after that will be more of the samey. I heard that is Lerche of will adapt it.