this is a "harem type game (The mc is the only men with the girls)" or a "Share type game (there will be more mens in sex escenes)"?
What if you add a couple, the lover boy and mc bonded, and then he got isekai truck'd. Before dying, he says some final few words about taking care of his lover. After his death, the mc can start rizzing the girl. Making every memories of the girl with his now-deceased lover being replaced with mc. Muahahaha 😆😆😈