Hi, OP!
I fixed my long standing plantar fasciitis with stretching, but a very specific kind. It is important that you hold the stretch for a long period of time, longer than most people usually do. 2 minutes per leg. And you need to do the stretches daily, for about a month.
I learned about the stretches here on DCUM; the poster posted a link to this video that explained the stretches.
https://www.youtube.com/watch?v=RRDC8erSNqw&t=142s
I know how to be careful of taking medical advice online or from Dr Google. However, the stretches shown did not appear to be dangerous in any way; they were non invasive; they cost nothing; and the explanation given for why they would work seemed to make sense to me. Moreover, advice from my own doctor wasn't working and we were going to have to escalate to more invasive and expensive measures, so I gave the stretches a try.
After a couple weeks I definitely noted.lessened pain overall which gave me the impetus to keep doing the stretches. I used a timer to be sure I was holding them long enough. I didn't remember to do them every single day, but I did them very very often, for about 4 weeks.
It really helped, and my fasciitis is totally gone now.