Holly, about the arthritis, my sympathies. If it helps any to know this, everybody seems to get it in one part of their body or another, if they live long enough. It's pretty universal. In my case, it's one shoulder. (So far). The only "solution" is shoulder replacement surgery, which I am not interested in, unless it gets a whole lot worse. So I rely on pain killers when necessary, exercise, and finding ways to cope with it. (Like everyone else.) I've found that I can completely forget about it when my attention is distracted by something else. Maybe some day they'll come up with a vaccine or a magic cure.
About the downsizing, it seems to be an ongoing thing with most people, including me. I get the feeling that most of us spend the first half of our life accumulating stuff, and the second half getting rid of it. At least, that's true for my generation. I think young people now are different. They seem to travel much "lighter" than we did. They are not interested in collecting all the elegant furniture, china, crystal, silver, art works, etc. that our parents' and our generation did. In a way, I envy them. (A cell phone is a lot easier to take with you when you move.)
And even after two moves to smaller residences, I still find that I have more "stuff" than I want or need. I'm constantly giving things away to my kids and grandkids, who don't really want it either, but they take it out of politeness. The only stuff I have that is valuable to any of us is all the art work my late husband did, and everybody's walls are full of his paintings, our windows have lots of his stained glass creations hanging in them, etc.
One example of mostly useless stuff is my turntable and vinyl records. I still have them, but figuring out what to do with them is a major undertaking. I know there are shops that sell vinyl records, but mine are mostly classical (not exactly popular with the 21-year-olds who collect them), and then there's the problem of hauling them to the store, and probably going home with about $20. So they'll probably just sit here until I am gone, and then they will be my children's problem.
I don't think moving out of a house that's too big, or too much work for us is ever a mistake. We all need different things at different stages of life. I've found that in my later years, I have no desire or need for a large house. What I need now is comfort, safety, ease of maintenance, cleanliness, and above all, friendly people and activities, convenient shopping and cultural activities. And of course, being near to at least some of my family. Having beautiful scenery around me used to be a big priority. Now, I'm happy having reasonably pleasant scenery, not high on my list of "must have" items any more. I still wouldn't want to live in an ugly place, though.
I think the best thing is to "loosen up" and recognize that we might be ready for something different. What we wanted at age 10 is not the same thing as what we want now. And even giving up some things that we truly love is worth the trade-off for many other benefits. Not that everybody has to move into a hi-rise, of course. There could be a surprising amount of relief from just moving into a smaller house, and starting a smaller garden. Maybe try making your life a it easier with baby steps.