Actual game designers know that you make games using the reverse logic: how little should I add to have a viable and fun game? That's what Mark Rosewater, the head designer of Magic The Gathering, advises to people when making games. He also has a phrase he repeats often that people meme him about: "Restrictions Breed Creativity". A good game designer blocks their thought process to a few mechanics, and ask themselves every way they can explore the restricted mechanics they have to make a fun game, and in the case it's not enough, they add just a little more to get there. The video in which he describes these concepts is extremely good, by the way, I heavily recommend watching it.
Doing the contrary of adding a lot of things will end up with a bloated, purposeless game, which is what Yandere Simulator is: a game without true purpose, with mechanics that don't connect and sometimes overlap, and they do not even work. Make the game simpler, with a simpler set of mechanics, goals and obstacles, and perhaps Yandere Simulator can be made into a fun challenging game again. Otherwise it's a lost cause. You're working with a faulty base here.