Lacquer has been used for centuries in order to strengthen things like tools, weapons and even armor.
So I think it would be quite nice for a lacquer type item to be introduced to make quest weapons/armor last longer.
It could be a very rare drop from a boss chest.
Perhaps the weapon/armor peice could just be given extra max durability, or maybe extra unbreaking enchantments.
As of now, aside from usage during high tier boss fights, its quite inefficient to use things like angelic armor during lowtown/harvest field runs. (Mending armor can work just as well).
Given the benefits in the dps of angelic over other things, this could make it more worth to use at lower tier fights.