You say you’ve been suffering from extreme dryness since your early 40s—now nearly 30 years. From your description, I’m thinking that your symptoms are vulvar as well as vaginal. You say you’ve been tested for all kinds of causes; I hope that’s included a vulvar biopsy to rule out any vulvar dermatoses (vulvar skin diseases).
There are a couple of new, non-hormonal pharmaceutical options that I think it would be worthwhile for you to investigate with your doctor. I’d recommend that you trial Osphena for three months. This is a non-estrogen oral treatment for atrophy, and in my experience it’s been effective. There’s also a new product called Intrarosa, a vaginal insert used daily. Both of these are by prescription, so another discussion with your doctor (and if you’re not entirely confident in your doctor, seek out a menopause care provider) is in order. And neither focuses specifically on the vulva, but typically what helps the vagina also helps the vulva.