I find yoga (just through youtube) very helpful... without it I feel like the Tin Man. Also, I joined a site called autoimmune strong that has exercises designed for people with autoimmune diseases. Small, Slow and Steady seem to be the key. I also bought a device that picks up stuff for me so I don't have to bend or reach.
Hope this helps...

For a long time, it was painful to move, and so I moved less and less and less. In January of 2021, I came around and committed to regular exercise for an entire year. I joined a local fitness center that has small group (max 10/class) classes. I went almost daily (still do). At first, I hated it. Every muscle hurt. My back and hips screamed at me...but after a while, I got stronger. I started to notice that when I exercise, my pain is alleviated for a few hours. It worked so well, my husband and I also started walking daily. We now walk an average of 3 miles a day. It's a big part of my treatment plan.
Good luck to you.

Also...I looked up AS stretches on Youtube...I can't even do 90% of what they show. I can turn my head! lol So much for my GP's "Urgent Referral".