Make mending only appears in tresure chests, And improve the Anvil.

Make mending only appears in treasure chests, but make it compatible with every incompatible enchantment. That way, we could get more overpowered, but it will be a great cost of seeking out,going out and seek ancient cities, end cities and so on. Also make the anvil useful and unbreakeable, so we dont depent too much on mending.