On the Steam Deck, is there a way to edit the back buttons in Keybindings?

I’m playing on the Steam Deck and want to edit my keybindings so I can use the back buttons, aka R4, R5, L4, and L5. Currently these buttons zoom in/out the world and minimap. When I attempt to change what one of these buttons does in Keybindings (I want to use one of them to grapple), the button won’t register. I also can’t find them anywhere in the Keybindings menu.

Am I missing something or are you not able to use the back buttons for anything else but zooming in and out?