The syndrome can be explained by a neurovirus for 80% of people. Any doctor that thinks it is not has a vested interested in proving it is not, and they have not, so fuck them.

Thyroid is pretty easy to treat. Go hard and ignore your test results - who cares? There is more evidence that CFS is more similar to hyper- rather than hypo- thyroidism (as the inverse of dysfunctional cortisol), but go for it.

I am not sure, but I will address some of the options you mentioned. The gut microbiome is the biggest bottle of bullshit being touted by patients because alt med docs love the simplicity of prescribing antimicrobials (it never will put their license in jeopardy), if you investigate cure claims closely they relapse brutally. UCD and Crohn's for the most part are treated with therapeutics unrelated to anti-microbials, and helminth success has been mixed... if you took albendazole before you got sick that may be something to look into.

Heavy metal poisoning treatment is a dead-end because it has a one-way ticket into the CNS, you would actually be taking it out of lymphatic tissue, back into circulation, then into the CNS, worsening symptoms. Might want to consider extraction if you have mercury amalgamated teeth, and not the special removal touted. Just stop eating fish period, because why would you? Other than that, in 2019, it is going to be difficult to treat.

You being "low" in nutrients could be a compensatory mechanism defending against infection, and I would not trust plasma levels for the most part anyways.

There are some banana stories about one chiropractic adjustment completely curing CFS. What makes these stories interesting is that there is no singular person or chiropractor that benefits from cervical correction, as in you might receive the same care in rural north dakota as the best chiropractor in New York City.