Personalized enchanted book with too high a value does not work.

Give a custom enchanted book with a level beyond the limit of enchantments.

Exemple :

/give @p minecraft:enchanted_book{StoredEnchantments:[{id:"minecraft:unbreaking",lvl:5}]}

/give @p minecraft:enchanted_book{StoredEnchantments:[{id:"minecraft:sharpness",lvl:10}]}

/give @p minecraft:enchanted_book{StoredEnchantments:[{id:"minecraft:protection",lvl:50}]}

Merge this enchanted book with item.

 
Enchantment becomes equal to enchantment limit.