A few suggestions:
When the cursor is at the bottom most grid of the inventory, pressing down should wrap you around to the top slot of the inventory (torch slot).
Would it be possible to make the RB/LB menus modal instead of hold? Tap RB brings up inventory and while it is up face buttons only control inventory, tapping again closes and face buttons return to in-game functionality.
It's a bit of a strain to need to hold down LB/RB the whole time when you are trying to interact with the inventory
Font scaling would be helpful as well. It's a little bit too small at the moment