We love our 2020 Wolfpup 18TO, but felt it was a bit lacking for luggage storage. (Lifting the bed to get something out of a suitcase is annoying.) We came up with a convenient mod: installing shelves on the back wall, that fold down out of the way when the bump-out room is retracted. (The real challenge was that the bump-out is only about 6 inches from the wall - too close to leave useful-width shelves in place when we retracted the room.)
The folding shelf brackets we selected were not cheap - $30/pair - but we wanted stainless and high-strength. This is what we selected:
https://www.amazon.com/gp/product/B07F3RBFXC/
We selected prefinished shelves from Home Depot, mainly because they matched the color of other wood trim in the trailer, and didn't require cutting to size or finishing.
I mounted the shelves to the two studs in the wall. It took a bit of careful work to find the studs, even with a stud finder, but the real telltale ended up being the tiny staples holding the panel to the studs.
They're sturdy and haven't had any trouble holding a couple of suitcases, clothing, and some other miscellaneous stuff.