I don't know the limit of how many cortisone injections - I have no experience with that - thankfully.

You ask what else can help? I think...
-- OTC pain relievers and prescription pain relievers.
-- Hydrotherapy is usually helpful.
-- Moderating your activity can be helpful. Example: I avoid repeated lifting of objects like picking up yard debris and do zero lifting of heavy items.
-- Physical therapy can be helpful.
-- I have heard some supplements may help, but I've not had much success with them. See: https://www.arthritis.org/health-wellness/treatment/complementary-therapies/supplements-and-vitamins/supplements-for-arthritis

Hope this helps.