how to .duplicate a node while also copying all of its child nodes

How to save node like scene via code - #2 by system Does this help?

But generally for a level editor/similar you don’t save nodes or scenes but simpler data. For example for a tile-based map you might save a grid of tile ids.

Example, 0 could mean grass, 1 bush and 2 a tree. The idea is to save only as much data as is needed

var map = [
[0, 2, 0, 0],
[0, 0, 1, 0],
[0, 1, 0, 1],
[0, 2, 0, 0],
]

But level editors can be hard to make, especially for a beginner. Good luck!