Don’t try to bend the panel, create a radial array of the slats using Rotate/Copy and rotate about the center of the arc of the wall. Make as many as you need. I just made 12 copies here.
Make the backing for the panel the same way you made the curved wall.
I have tried to follow along with your explanation however when I try to use the protractor and lock the plane my lines from the protractor don’t follow along the curved wall and instead show up outside the curved wall
I have looked at the setup of your demonstration and it seems that your protractor is setup differently
is the marker that you setup on the wall directly on the wall ? of is it off the wall
I have mine directly in the centre of the curved wall and the protractor shows up like this
This is a simple example of a radial array on a specific arc.
Note the arc and the group are separate. I select the group the use the Rotate tool (not the protractor) on the blue axis to array the copies around the centre of the arc.