Oh wow you have really been through the ringer. I am so, so sorry about your suffering. My heart goes out to you!
When you said vertigo, I kind of though ME/CSF. There’s an author named Laura Hillenbrand who wrote an exquisite essay about her journey into CSF hell that discussed vertigo as a primary symptom. Anyway, the reason I mention this is because an emerging treatment for that illness is Low Dose Naltrexone. It prompts your body to produce natural endorphins, which modulate the immune system. I am on this to control the pain and inflammation that comes with EDS. I can’t describe the degree to which that drug has helped me. My inflammation is gone and my pain is gone. This is after a lifetime of terrible pain like you described: neck pain, headaches, and also burning inflammation throughout my joints and muscles.
Hugs.