Is it intended that you are only able to make one of these spawners? You can only get 1 egg from the first time you kill the ender dragon.

In vanilla Minecraft / Apotheosis, you can only get one spawn egg per world. However, you can make a datapack to change the modifier to need a different material. There's also mods/datapacks out there that make it to the ender dragon spawns an egg each time it is killed.

Thanks for the info, I'll look into it!