The only ADA compliance shops that I can ever remember seeing were for K-Mart in 2009 or so. They didn't last long and I can't recall seeing any since then. If you are in an area with Kroger stores, they would seem to be an option since supermarkets in my area (no Kroger stores and the supermarket chains in my area stopped doing mystery shops in early COVID days) generally provide motorized shopping carts, so your scooter would work for you.
I suggest that you also look for telephone and internet shops that you can do from home. Other reasonable shops that come to mind would be visiting banks. I can tell you that many business compliance (with financial aspects, not ADA aspects) would be challenging or impossible and the shops clearly state that the MSC can not guarantee easy access. You might want to consider mattress store shops, but only you know how easy (or hard) it would be for you to lay on and evaluate multiple mattresses.
Shopping Southeast Pennsylvania, Delaware above the canal, and South Jersey since 2008