Also, with homogeneity, there was no point to collapse to, so I’ve seen stated, not that it’s a strong argument.
You seem to have missed my point, there.
If space did not expand the lump of matter in it when space itself expanded, then there would not have been "no point to collapse to" because space would be larger, and empty except for that still only 6 km diameter lump of matter. So, for the homogeneity of the universe to be maintained during inflation, the matter
must expand with the space in that theorized early universe.
Another way to look at it is that, if space were to expand so that different parts of it had relative velocities far exceeding the speed of light (which is what is theorized), then, for matter to not expand with it,
matter must have passed through space at greater than the speed of light.
The only
consistent way to theorize that space inflated dramatically faster than light speed is to
assume that the matter in space expanded/ diffused along with the space, and I believe that is indeed what the BBT theorizes. Otherwise, it could not have turned quantum scale density fluctuations into the macro density fluctuations seen in the cosmic microwave background radiation and attributed to inflation of quantum fluctuations in the early universe.
The question remains whether there is some connection between quarks, baryons, atoms, or clumps of atoms ranging from dust to galaxies that is somehow including "space" that is
not expanding
now. My take on that is there seems to be no valid reason proposed for why space in such objects is not expanding now, when it is clearly a requirement of the theory that space in such objects expanded when the universe was much younger.
It just seems like another example of inconsistent thinking among folks who are convinced that the BBT model is correct.