You did not mention where you started on your PMR Dx and prednisone dosage or where you are now plus the extent to which your symptoms are being managed with your current dosage. This helps frame where you are on the PMR spectrum. If you never had to take more than 30mg of prednisone to manage the pain you then your case would be milder than someone who needed more. Also, have you tried to taper down any yet? This process needs to be slow and should be based on your inflammatory test numbers plus how much pain you are having. The goal should be to stay at a prednisone level that keeps you pain free before tapering down any, then if your inflammatory numbers are good, taper a little.
I had a conversation with my Endo recently and she said that checking my cortisol level while on prednisone has no value due to the prednisone masking and/or depressing your adrenal glands efforts. I have been at 10mg prednisone for 6+ months before I was able to come down any. I am now at 8mg and suspect I will be here for a number of months as well.

I not only have PMR, I also have GCA, so my dependance on prednisone will most likely be a lifelong need. I tried a biologic to taper off prednisone, it was working well until I had an adverse reaction at 10 weeks, so stopped that. Not sure what is next. Just know there is no single right answer. PMR is complex and not well understood. since there is no definitive test to confirm the Dx they do not really know if everyone who is Dx with PMR really has just one problem or multiple problems.

I wish you success on your journey. You will find this chat room very helpful and supportive. Please stay connected.