Since this is a chronic problem, you need to understand that a lifetime of steroids is not in your best interest. You need to think about reducing and/or eliminating your steroid intake as much as possible. I am on this roller coaster myself due to an adverse reaction to a biologic I went on with the goal of getting me off my steroids.

I asked my AI tool, MS Copilot, about the standard protocol for your Dx and this is what it told me -
"There is no single standardized protocol for multicentric reticulohistiocytosis (MRH), but modern evidence supports a stepwise, immunosuppressive regimen centered on methotrexate + systemic corticosteroids, with escalation to TNF‑α inhibitors, IL‑6 blockade, or JAK inhibitors for refractory disease. "

It appears to me that you doctor is moving from just steroids to steroids and methotrexate before moving to newer drugs. Please read up on the known side effect of any drug they want you on, including prednisone, so you understand what a reality for you could be. Many of the newer drugs have significant side effects that you will need to watch for if you go in that direction at some point. In all cases you need to arm yourself with information of the potential side effects.

I am sorry you are on this journey. I wish success as you partner with your medical team to find a successful and acceptable treatment plan.