I had the privilege of dealing with water damage in our coach's rear walls. I say privilege because I pulled this thing down to the exterior walls. I now know more about what's going on between the interior and exterior walls. Our coach's walls are a good 2" thick. I replaced the insulation and put up new interior walls and most things, like the curtain hardware, will hold in place well with the small-ish screws I used (I made our own curtain hardware).
If you really get into something then build that from the floor up. For our new rear closets I support them from the cargo box and there are only two screws into a wall for those. The floor is doing the heavy lifting.
Your coach is much newer than ours and in such maybe you are not ready to dig into it ... yet. Our coach is our home and as such I'll jump in and change it up to work for us.
** For those who are asking themselves about the Emergency Exit behind the artwork. It's still there and the artwork is hinged in case we ever need to bail out the back. Let's hope that is never necessary.