Having Librarian villagers sell a custom enchanted book (1.21)

There is a datapack that we use in a server that creates custom enchantments and enchanted books, however, a specific book isnt traded by a villager, so I want to make a datapack that adds that trade to the Librarian Villager trade pool (with ideally a much rarer chance than mending). Image attached is a screenshot of the components of the enchanted book I want villagers to sell. How would I accomplish this?