btw, i have found this plugin, but it is not for Godot 4.
anyway, maybe it will help you in developing.
https://godotengine.org/asset-library/asset/878
the idea is you can just add nodes
as "tiles"
and place on scene
maybe like
@export var block1 = load("block1 scene")
@export var block2 = load("block2 scene")
#then place on x,y,z in editor.