Do you sometimes wish you could press a face button without taking your thumb off the sticks? If yes, then controllers with back buttons are going to work well for you. Otherwise not really.
My problem with edge is just that I think $200 is totally overkill. Unless you are playing professionally I don't think paying close to half the cost of a PS5 is worth it for a controller.
That being said, back buttons are handy. What features interest you the most?
I wouldn't recommend shopping on Amazon in general, but in this case specifically, I would recommend checking Warehouse Deals for the Dualsense Edge. That's how I got mine for 40% off MSRP and it was pretty much brand new. It's honestly the best investment I've made since getting my PS5, hands down.