The hot glue didn't end up sticking after a few days. I ended up pealing it off (left no residue). That's ok though, it was more of a proof of concept.
I'm still looking for a permanent solution because I really like the orientation and stability in landscape mode that the apple case provides with the strap positioned in that location.
You can see when I'm pressing it how well it transfers the weight and helps prevent the slippage.
I need a silicon solution, or whatever professional method they use to coat the edge of something like this with a rubberized, rounded edge.