I have had GPA (formerly known as Wegener's granulomatosis) for twenty years. I worked in an old building that had a lot of asbestos and three of us came down with GPA. It took me several years to get diagnosed and I had to almost die to get a correct diagnosis. With treatment and lot of rehab I survived and after a couple years reached my new "normal level of functioning" and had to seriously downsize my life style. But the near death experience and one serious relapse caused by covid vaccination, have give me a great appreciation of the miracle of still being alive 16 years after my diagnosis. If you are lucky enough to get properly diagnosed early so you can avoid the most serious body damage, one can have a pretty good active life. Many people even attain a drug free remission. I still need 10 mg of prednisone and occasional RTX infusions to control my GPA.
I was active on a forum for years with other people with PGA that I found very helpful. It may have ended due to large decline in members and activity as people switched to various Facebook groups for support.