Hi @bayhorse, I myself haven't tried an all plant based diet but hopefully others that have can share their experience with you. There is another discussion on the same topic in a different group here that might be helpful:
--- Plant-Based Diet to Mitigate Prostate Cancer: https://connect.mayoclinic.org/discussion/plant-based-diet-to-mitigate-prostate-cancer/.

While we wait for other members with experience to join the discussion, I though you might find this information helpful if you haven't already seen it.
--- The Benefits of Plant-Based Nutrition: Treatment and Prevention of Autoimmune Disease:
https://lifestylemedicine.org/articles/benefits-plant-based-nutrition-autoimmune-disease/
--- Plant-Based Diets and Autoimmune Disease – 7 Reasons You May Not Feel Better: https://eatandlivehealthfully.com/plant-based-diets-and-autoimmune-disease-7-reasons-you-may-not-feel-better/.