Hey, I'd be glad if you could add this mod.
CloneLand: https://www.curseforge.com/minecraft/mc-mods/cloneland
Adds a staff and a block which can both transport you to another dimension which is a perfect clone of the overworld. It also works with the nether. It can be used for puzzle maps and hiding secrets. Also e.g. if you find a rare ore, you can just mine it in the overworld and in cloneland too.
