Is it empty, or full?
It is neither. It is flat and unknowable from the 2-D perspective. To make a cylinder or sphere of it requires an extra dimension, or the illusion thereof via our flat technology.
So it is in the 3-D universe. A hypersphere is only depicted in our XYZ + Omega/Time dimensional POV, just as a cube is only suggested on paper. From above, the world we know looks flat, or rather a plus-dimensional flat. Flat, but more, if you prefer. An entire hour of your life is a hum-drum simulacrum in media of the higher dimensions, failing to capture the verisimiltude of reality. And in failing, obscuring details. Information is lost, undepicted in its inferior context.
You know what this means, don’t you?
We can hide secrets from God.