I do not know if this could be relevant, or if you have been tested for this. I had suffered for 12 years with sporadic bouts of leg paralysis, ataxia, hip joint pain after a bad infectious mononucleosis infection that hospitalized me. I had been tested over and over for things like Lyme, MS, Lupus etc (all came back normal). After seeing many neurologists, rheumatologist and endocrinologist, I was was tested by a GP hospitalist for gluten, and found out that I have Celiac Disease. (Simple blood work followed by endoscopy while remaining on a gluten diet is all that is needed). This revelation has shocked my specialists. Celiac Disease has over 200 symptoms unrelated to digestive issues and is often a mimicker of other diseases and can be the cause many neurological problems. It often pairs with other autoimmune
illnesses. I don't know if this could be helpful, but it may be worth looking into. I am so sorry you are going through this and I hope you find answers and feel better soon!