We are not so far apart it would seem.
A shrinking universe is much more consistent with attractive force of gravity and charge, but the fact of mass decay is one of dephasing while mass gain would be rephasing.
My universe is closed and bounded and so the limits of what we see are the limits of the universe. Since certain constants like c define the universe collapse, this changes the nature of the light cones that limit events in GR.
Actually, all that remains to validate a shrinking universe is more sensitive measurements to further validate the decay that has already been observed but dismissed as an artifact or an effect of tidal forces or gravity radiation.