My wife has one, I don’t like to use it, it’s too aggressive for me.
I can reach my back with my arms. To get the spot right between my shoulders I have to reach up and come down from the top with one arm, while using my other hand to grab my elbow and pull it to push my hand low enough to get it more effectively.
I’m on silverblue, well, bluefin, specifically.
So far so happy 🤷♂️