I may be wrong, but if you will need different logic to interact with different types of assets on the map I think you will need to import these as different scenes and place them in the engine.
For assets which are repeated a lot, you can use MultiMesh to accelerate rendering.
I see now I wasn’t super clear in original question. I’m trying to figure out which on would be more efficient for Godot to render. (All the geo would be static)
A large map that is pre-built/arranged with all the textures on one large texture map?
Or
Importing all the repeatable assets seperately and building the map in Godot? Instanting all the various assets.
Also, I have to look more into multi-mesh, If I can populate mesh in specific designs, than I may give it a try.