Just listening to this interview with the author of the book BUILT TO RUN.
He has some really useful suggestions for runners that have heel pain, plantar fasciitis, Achilles tendinitis, etc.
Basically, the classic heel drop, both normal and with bent legs, is advised. If needed weighted as to get rid of PF you need to load the arch. That’s his No 1.
Also a section on linking the desire of feet and toes to spread as an essential, as the arch only stiffens automatically when the toes / forefoot is stretched, so wide toeboxes are essential.
Link here to Apple podcasts: