Item sorting QoL is a nice change! It's less of an issue with the Weapon inventory than with the Accessory inventory, but since all Weapons are simply of type "Weapon", sort by Type does nothing there. This could be fixed by adding Weapon subtypes in the same way that there are Accessory subtypes, tagging each item with something like Weapon (Sword), Weapon (Bow), Weapon (Restraint), etc...
Alternatively, since the only thing the player probably cares about in the Weapon inventory is which Weapons can be equipped by the active character, a Separate filter for "Equipable" would conveniently group all the items you're looking for at the start of the list.