Since the formation of fundamental particles at the beginning of the universe (roughly the time of the CMB emission, and after the inflationary epoch of Big Bang theory), the gravity wave front of all particles in the universe (which propagates at c) has been continuing to spread. Therefore, for the exact same reason our "observable" universe is limited by the travel distance of photons since the CMB, our local gravitational potential shifts over time for the same reason.
Calculations I've done for this result in a linear trend of this GP accumulation which matches all measurements of red shift to this point. Although I'm not taking about metric expansion in the Hubble Flow sense, distances would still be expanding between all points relatively (time dilation).
I understand that Hubble and Einstein did not believe in a cosmic origin, so doppler effect was the best hypothesis at the time. However, since a finite time universe has become the prevalent theory since their deaths, has this gravitational solution been considered?