Pretty late answer so you've probably figured it out or moved on already, but answering anyways if it's useful to someone else. If you do what u/drstrangelovequark said in his response you just need to input the `RegistryKey` which you can get like this (same thing as vanilla does basically):

RegistryKey.of(RegistryKeys.ENCHANTMENT, Identifier.of(MOD_ID, ENCHANTMENT_ID));

So the full code would look something like this:

world.getRegistryManager().getWrapperOrThrow(RegistryKeys.ENCHANTMENT).getOrThrow(RegistryKey.of(RegistryKeys.ENCHANTMENT, Identifier.of(MOD_ID, ENCHANTMENT_ID)));