I would suggest that you get your hips checked out. I have had idiopathic PN for several years. Last year, April 2024, my R leg started giving out under me. One day it did so repeatedly. The next morning I went to the orthopedic Urgent Care clinic. X-rays showed the hip joint was arthritic. An MRI showed that the bursa was not contributing to the pain. As soon as I could get on the schedule, I had a hip replacement. The new hip does not go out from under me, and the pain I was attributing to my lower back or sacroilliac joint turned out to be removed by a hip replacement - the pain was coming from the hip. Good luck as you search for the cause of your problem.