I loaded all the chunks within a large border, and set the world border to the edge of the giant area.
I loaded all dimensions, as well as replaced the elytra in the end cities that pop off normally, leaving them on a single piece of endstone in their exact location.
There is no need to download the mod, so it is easy to set up on a server, at the downside of it being a large file.
It uses the original seed used by those in the ProtoSky server, with starting blocks, world spawn, and starting bonemeal already set.
If you have issues and spawn in the overworld, use the following commands:
/execute in the_nether run tp @p 0 65 0
followed by:
/spawnpoint
If your bone meal doesn't work, just try again with:
/give @p bone_meal
Let me know if there are any other questions!
This was made rather quickly as I'm eager to play, so let me know if there is any issues! Goodluck!