By the way, the reason I started taking methotrexate is that I have something autoimmune causing low blood flow to the brain (or at least that's what the researcher in the US who studies OCHOS says).
I did see a rheumatologist who was okay. Not awful, but not brilliant either. He tried me on LDN (worked but gave me awful nightmares) and hydroxychloroquine (got rid of pain in my hands and wrists but didn't do anything for the cerebral blood flow).
Usually methotrexate would be the next-step DMARD for someone who didn't respond to hydroxychloroquine, but the rheumatologist said I wasn't sick enough to to have it. (On other fronts, he said I could have it, i.e. there's nothing wrong with my liver that would be a contraindication.)
My researcher, Dr Novak is giving a talk soon at the Dysautonomia International conference about using IVIg on his patients, possibly including his OCHOS patients. I would never qualify for IVIg here, but I might be able to use his lecture to convince them to step me up one level on the DMARD front.
DMARD stands for disease-modifying anti-rheumatic drug. There are about ten of these (varies a bit according to which autoimmune disease is being treated) and they are roughly arranged from weakest/least risky to strongest/most risky. If those don't work, then come more fancy (expensive) ones such as biologics, JAK inhibitors, and possibly IVIg.