@ghosteevees would you be interested in mixing these ideas together? Just, just Hear me out
Reader cross dresses to go to a boys school to escape her last school, where she was a witch and a bunch of yandere monsters were after her. But, while trying to fit in while hiding the fact that she is a witch AND a girl, she and her new friends must deal with the mysterious deaths of their classmates, whom may have been killed by one of the monsters from her past school.
Its kind of a mess, but if you end up not being able to choose could this maybe be an option?