I'm almost 70 with osteoarthritis and here is what I've learned about cortisone shots:

30 plus years ago the thinking in the medical community was that three cortisone shots was the limit for any joint. Beyond that they feared ligament and tendon deterioration.

That's changed and more than three shots in a joint is not uncommon. My left shoulder could be replaced today if I wanted, it's bone on bone. But I can still raise my arm straight up with some pain, not terrible. I can still do almost all the things I want in the gym. And even that pain goes away with a cortisone shot when the pain/discomfort returns.

Once the joint (any joint) gets to the point where you can't do normal activities, it's time for a replacement. For example, if you can't use stairs, it's time for a knee or maybe hip replacement. I've had both knees replaced with great success.

And I have found cortisone shots to be fickle. The last one in my shoulder was great. I've been pain free for well over 6 weeks. Before that, I've had shots that sorta worked, and shots in my knee that seldom worked.

Anyway my advice is that if you can get through the day without a lot of trouble and you can sleep, stick with the cortisone shots and put off the surgery. Otherwise, find a good surgeon and get the replacement.