Villagers dont need changing

It takes a great deal of effort and time to make villagers overpowered, they don't need enchant nerfs and they certainly don't need enchants to be biome specific

making better enchants come at at higher villager levels is a good idea
but restrict that to level 4/5s and mending
making biome specific makes it so much harder to get good villager setups
and making the books less likely/never max level makes anvil exp a massive issue