I bet flat-world theory actually holds true through perspectives of intra-dimensional beings.
To exist in moving material, our universe, and be of multiple other realms at once!? It would be as if our sixth sense, which is a momentary, extra-sensory perception, has root in another dimension of ‘space’ (the room just off the end of the hall) at all times and is perceived by them as a constant piece of reality. It would be as if they perceive more foundations of reality than we do and they perceive them in ways as common and inherent to us as light & vision. It would be as if through their eyes space appears bent, on a slope, beaded upon another element of their conscious existence.
That is to say, perhaps the gods walk across the place of our universe seeing but marbles for galaxies, stars, and planets.
What in imagination is to say otherwise?