Something that has raised questions to my mind is the similarity in ratio between the apparently missing primordial anti-matter and those of dark matter. So….
As gravity has a square of the distance nature in it’s effects upon the visible universe, might it not also have a similar equation that deals with mass separation in time? I don’t know of a definitive reason that a matter and antimatter universe could not occupy the same relative space, being separated only by each lobes path within it’s spacetime trajectory.