I found a slide shovel with effi 5 in a bastion, I can do the enchantment on a book
An enchantment can't be removed from an item. However, you can enchant the books yourself at a magic table.
No, you can only take the XP from it (not worth it).
If you have Villager, then you can build a Villager Breeder and a Trading Station. Then you can put a lectern next to a villager and take it down and always see what kind of enchantment he has.
If he is lucky, he will quickly have an Efficiency 5 book on offer. However, if you are unlucky it will take a long time.
