Not really a source, but this Dental Hygienist talks a bit about hydroxyapatite. Sounds like it could be of at least equal effectiveness. Though further studies are needed.
https://youtu.be/kQAPEZaqwfY?t=63
Not OP but I have a family member who’s a specialized dentist who’s well regarded in the field and constantly harps on this kind of toothpaste over fluoride. I think fluoride is basically cheap and that’s all