What feature do you want to see added?

create world in async thread

Are there any alternatives?

I used com.boydti.fawe.bukkit.wrapper.AsyncWorld in mcversion 1.8 to complete this requirement, but I couldn't find any clues about it in mcversion 1.19

Anything else?

No response

Such a feature should be provided by the server software itself. Otherwise, it's our burden to maintain it (which is why the functionality was removed).