It is simple but you need to understand how to use follow me.
A profile and a path.
On phone but im sure someone will quickly give you a vid.
One way to explain it in words.
Create a cube or rectangular prism if need be. Draw an arc from top to bottom as you want it. Select the top face, activate the follow me tool and click on the face to the outside of the arc.
I may not have been specific, the arc should be on one face. Also be sure you aren’t playing around with tiny things. If your whole thing is less than 50mm then you’ll get problems.
This is about as close as I can get with a crazy work around.
I want a single arc to go from the bottom corners to the top corners, 45 degrees from the corner (like in the original photo, but with nice clean faces.