Where do you live that you are 5 miles from a grocery store? If I ride my bike 5 miles in any direction I will pass half a dozen grocery stores.
I had a quick look at Google Maps and there are at least 50 supermarkets within a 5 mile radius of my home. That radius covers the whole of the city I live in, which has 38 supermarkets, plus a sizable portion of the neighboring city, which has 24, plus a few smaller villages which all have at least one.
I went grocery shopping twice today. Once this morning to pick up some breakfast stuff and another visit in the evening to get some things for dinner. It’s a 3 minute bike ride. A grocery trip takes less than 15 minutes including the time spent in the store. I don’t think it’s possible to live farther than that from a supermarket in this city, I lived 1 minute farther away I would be closer to another supermarket.
Three-wheeled e-bikes (trikes) also exist. I know someone who also has balance issue (mid 40’s with reduced motor control on one side of the body) who uses one all the time.
They are also used a lot by elderly people who are afraid to fall over. A friend of mine’s mother uses one for that reason. Depending on your needs they come with either a normal bicycle saddle or even a full seat if you need the extra support.