I've read about this. There does seem to be mounting evidence that stem cell treatment for ED can be effective. https://www.medicalnewstoday.com/articles/316555 But I think the biggest barrier is finding access to it and affording it if you can. It tends to not be something all that readily available (maybe because there still is some controversial aspects to stem cell usage for some reason) and it tends to be very expensive. Is this something you've researched as available near you?
No personal experience w/ it, I’ve heard of it, some say it works, but not sure there are any clinical trials that price it works. That’s not to say it doesn’t, just that it hasn’t been proven yet. Do a lot of online research about it, you may be able to find testimonials from guys who’ve had it & say it worked for them.