Why is there so many rules around movement with autoimmune diseases???

Ever since i have been diagnosed with Hashimoto's I have heard countless rules of what I should do. I experience any bad symptom of the condition or maybe the medicine and I hear doctors forever underplay it and bring down an endless list to try. Tiktok says do low cortisol movement, hot girl walks, pilates, no gluten, no refined sugar...just endless rules while my doctor is ALWAYS saying "well your levels are fine".

This situation made me get into PA school, and for reference I am also a certified yoga teacher, to try to bridge this gap that I felt and I am sure so many others have been feeling. Curious if anyone has tried anything that has genuinely helped or feel just as lost as I am and need a roadmap.