Append world data?

You can use additively-loaded scenes all day long.

In fact, just 100% of all projects I do nowadays additively load scenes.

A multi-scene loader thingy:

My typical Scene Loader:

Other notes on additive scene loading:

Timing of scene loading:

Also, if something exists only in one scene, DO NOT MAKE A PREFAB out of it. It’s a waste of time and needlessly splits your work between two files, the prefab and the scene, leading to many possible errors and edge cases.

Two similar examples of checking if everything is ready to go: