Jan, I'm sorry that you feel "No one seems to want to help me solve the puzzle of what is causing my peripheral neuropathy," The truth of the matter is that often there is no known cause. Once they rule out the obvious - diabetes and a few other diseases, pinched nerves, etc - there really isn't much more medicine can do at this point.

Perhaps, if you are near a large research hospital, you can find someone who is researching the causes of neuropathy and become part of a study.

And in truth, it is not only neuropathy. I have a progressive lung disease known as bronchiectasis and doctors can theorize about what caused it - undertreated asthma, exposure to bad stuff in the air, repeated pneumonia and lung infections - but we will never know for sure. In the end, it doesn't matter, because it just needs to be treated and managed to make my breathing and my life the best possible. The same is true of many cancers and other diseases.

Someday the genetic and environmental puzzles may be completely solved, and research into these is constant, but in the meantime we treat the symptoms. Have you read what Mayo Clinic says about neuropathy?
https://www.mayoclinic.org/diseases-conditions/peripheral-neuropathy/symptoms-causes/syc-20352061