All of this doesn't work since one could kill Osana during the first day despite Alex's autistic attempts at putting bandaid over rotting flesh i.e. making her bodyguard invincible and all knowing. The rest of the week is for nothing.
Given that YS was supposed to have social school simulator as its secondary genre, it would make sense if even when there's no current rival, there was meaningful things to do in the school that help you prepare for the next rivals. Killing a rival should not be the focus of the entire week. You don't need to lay groundworks for stabbing a schoolgirl for four whole days.
a YANDERE Simulator with a protagonist who is basically a robot who wants to mate with a plank of wood known as senpai
The reason senpai is a plank of wood is because the game is based on yandere media, in which the male character is the protagonist. He's bland for the viewer/reader to self-insert. When you switch perspectives, it kinda weakens the premise.
It's like rewriting Twilight from Edward's perspective: why should a reader of such a rewrite care about Bella, a plain, boring girl with no personality, when the main character is now a cool, powerful, sparkly vampire?
This is why Yandere Simulator doesn't feel like a romance story, even though on the surface it should. Senpai could stop existing and the rivals' Friday confession could be replaced with any other excuse of a deadline, and the game would be virtually the same.
A way to make weeks less boring and senpai more interesting, could be implementing "elimination" methods that are focused on making senpai reject the rival. This would mean figuring out what would make senpai reject the rival (which would mean giving senpai some personality) and either digging some dirt on the rival, making the rival do the wrong thing (by convincing or threatening), or spreading bad fake rumors about the rival (all of which could be done simultaneously, would require multiple actons, and therefore could be spread across the entire week).
For example, you could learn that senpai loves animals, you could then find a kitten, force Osana at knifepoint to kill it, record it on video, spread the video around the school, and then on Friday, hear senpai saying "sorry, I won't date kitten killers".