Should've just done more Hogwarts. Had the recipe for an easy cashgrab with "magical school" and you can even dream of continuing it a la Doctor Who by rotating the cast every 7 years. People love magical misfits and "magic school" is such an easy genre to write if you've got a captive audience of millenials that will watch any half-decent potterslop.
Honestly the big issue is Rowling. Both as a writer (she won't really let go of the property and involves herself with every project, making it worse) and as a person (she sucks and people hate her. Her not only making money but being involved with a project makes it toxic to a lot)