@vellen I think you would get a lot out of looking at this site : https://www.pmrandil6.com/ click through the top tabs over to resources and and scroll down to find the Video About the Pathophysiology of PMR and the Role of Elevated IL-6 in PMR.
I like this figure (below) from Lundberg et al 2022.

Steroids inhibit T-cell activation, proliferation and polarization into Th17 cells. In
addition, they trigger a decrease in the level of serum IL-6.
There are many of us, recently Diagnosed, that did NOT respond 100% to 15 or 20mg prednisone - a rheumatologist increased dose to 30mg for me - the miracle no pain no stiffness occurred next day !! {PS - it appears that a PCP is reluctant to go higher than 15 mg Prednisone - ASK your doctor to go higher ! - see if he/she says you would then need a Rheumatologist consult }
And you need to keep a pain journal ( I can give you some ideas if you wish ) - good luck !!