Yeah, well, that's cosmology for you.
Since this thread started, the Hubble tension has gotten worse, and some 120 new ideas about dark energy and its different modes and dynamics have been put on arxiv.
Also, Ziggurat showed me how to properly model the expansion of space (Thanks!) and hecd2 showed me how to properly convert supernovae data to distances I can compare with my models (Thanks!)
Now I have a simple z-distance relation that fits the empirical evidence with no other parameters z=HD2 +2HD.
It has been shown to me, in a variety of ways, that a slow photon does not reflect properly. Now I know that instead of the photon slowing down, it remains in c, but it has it's own clock that slows down with distance by 1/(1+z), or 1/(1+HD)2.
All in all, I think its been a pretty successful endeavor. But the real prize is the friends we made along the way.