Minecraft added a feature in 1.13.2
to be able to put enchant effects on the items. with this :

/give @s diamond_sword{Enchantments: [{}]} or with custom id.

To create DataPacks enchant it's great.

/give @s diamond_sword{Enchantments: [{id:"life_steal",lvl:1}]}

But everything does not work on spigot, not even /minecraft:give.
and it does not work with StoredEnchantments
Anyway this raises another problem /minecraft: <command> can not be put in the function this is considered as an error.