You cannot filter by region if you are using a controller. If you click in the right thumb stick to bring down the region selection, the confirmation button for the region select occupies the same input as applying for a cabal (A). This results in you attempting to apply to whatever cabal you have highlighted if you try to confirm your region filter selection. This is made more problematic in that controller and mouse support are a toggle rather than swapped on the fly so there is no easy way to make this region selection outside of disabling controller support, going back in, making the region selection, and enabling it again before playing.
Updates: Adding to this, navigating the actual Cabal list with a controller is problematic as well. You can use the D-pad to scroll down the list of Cabals, however, if you encounter a Cabal with a description that is long enough that you can scroll through it, the D-pad switches priority to scrolling through the description immediately upon selecting that Cabal and there does not appear to be a way to change focus back to navigating the Cabal list. This makes all Cabals listed below the problematic Cabal on that page impossible to select.
In relation to the Customization menu, while you can adjust the material for armor, it does not appear that you can adjust the "Sheen" pallet (or whatever this is) Added a screenshot for the area in question.