@tigertotheend. Sounds like you’re having a terrible time with local doctors! Can I suggest that you try a comprehensive medical center or a university teaching hospital. The doctors seem to be 1 step ahead of most community doctors. Or Mayo Clinic has a group of country-wide hospitals. You can try going to one of them also, no referral needed. This website gives the locations of the hospitals.
https://www.mayoclinic.org/about-mayo-clinic/care-network/network-members
Have you considered Long Covid? Do you have a Long Covid center in your area?