A smaller SUV might be just the ticket for you. Until I gave it away last year, I had a Subaru Forester. Getting things into and out of the back was a piece of cake because there's no "lip" to have to lift anything over. You'd have no problem with plenty of room for your Rollator. It was also as dependable as church on Sunday.
I understand that the smaller Kia SUV is also a good buy.
If you must buy now, go to CarMax or one of those big used car dealers that have their own mechanic shops. The best thing about them is that the price is the price and you don't have to dicker over it. There's no "I'll check with my manager" stuff. You can look online for the kind of vehicle you want to see what's available.
Try not to buy new. New-to-you is just as good from a used car dealership that warranties your purchase.
There's just one thing, and that is that right now is the worst possible time to buy a vehicle of any kind so if what you have now is still alive and kicking, try to keep it on the road as long as you can.
