Ms George,
Congratulations on the large number of books you have published to this point in your career (as I am sure it will continue - the voice is there.) Sad you are leaving Medium, but very understood. Why not give fiverr.com a crack? My beta readers for novels charge from 75 to 250$ per novel and they are exemplary at analyzing a book. With your background you would be a shoo-in. Plus proofreading could be a nice touch to the kitty. Let me know if you need some advice on fiverr or would like samples of beta reader work, along with the novel of course.
In any event best of luck.K