[Crossover] The Substitute No One Knows About

I got a plot bunny while doing homework →_→ I've still got a mountain of assignments lined up, and here I am coming up with ideas. Now I can't stop myself [covers face] It's probably about a player who plays a dating sim, then tries out a high-end version and ends up appearing in the game as the protagonist. They can only leave the game after successfully romancing their target. Anime, TV shows, movies, and all sorts of things might appear...