Viral Cause?

I've had tests for just about all of the viruses that are common. I had a strong antibody response to HHV-6, but when they did a PCR to confirm an active infection it was negative. So perhaps a post-viral problem, but that doesn't explain why multiple anti-viral agents have been so effective against my symptoms. When I had the thymus removed they tested the tissue for Adenovirus, Cytomegalovirus (HHV-5), Epstein-Barr (HHV-4), Enterovirus, and Parvovirus, all negative. I am positive for HHV-3 (Varicella Zoster) because I had chicken pox as a kid, so that remains a possibility of sorts. I was also tested for HHV-1, HHV-2 and RPR which was non-reactive. I had an MRI on my brain to see if there was any leakage of the contrast from any cranial nerves that would impact the esophagus - negative also, and that result tends to rule out a Zoster virus reactivation impacting cranial nerves as a cause (again, to some degree). That said, the fact remains that anti-virals have been critical to my ability to manage symptoms since Nov 2018. My perception is that medical science has not advanced to the point where they can provide answers on this. Some write-ups still indicate MG might be cause by a virus. Others indicate no known cause. Medical folks tend to get defensive sometimes when you present them with questions they can't answer - I get it, but unless they have evidence I can't buy into their theories, just as they can't buy into mine until I come up with some solid proof. I should point out that since they don't know the cause, they also can't say for sure that there is no cure, so I will continue to research my own situation extensively and have more tests done as I come up with my own theories.