You are not alone with having trouble tapering off of prednisone. It can be difficult for a lot of folks with PMR. There are many discussions on tapering down on prednisone that might be helpful to scan through - https://connect.mayoclinic.org/search/discussions/?search=Tapering%20off%20of%20Prednisone.

You might find the following tapering plan worth giving a try - Dead slow and nearly stop reduction plan: https://healthunlocked.com/pmrgcauk/posts/131189593/dead-slow-and-nearly-stop-reduction-plan

How long have you been on the prednisone, when were you first diagnosed with PMR?