The slide fix is called a "slide ski" which is a stainless steel plate screwed to the bottom of the slide for the rollers to run on. Because I knew about this issue, which is fairly common with all RV manufacturers, I watched closely for any signs of rippling on my 2020. When I saw some I wrote it up. Forest River authorized installation of the slide ski plates on all three slides under warranty. I'd guess they are about 1/8" thick.
You could buy them from Forest River but I imagine the shipping will be lot. The ones from FR will be cut to the correct size and have the countersunk holes for screwing them down. There's also an adhesive to help hold them in place in addition to the screws.
This company also makes them:
Guardian Plates | TALIN Manufacturing
Or you could get them manufactured locally if you want.
I don't know anything about the roof issue or the banging.
Ray