We are prematurely arriving at Hubble Constant and conclusion of acceleration of expansion in the Universe.
Nothing in Nature lasts for eve and follows DOB and DOD principles. Light propagating forever in Vaccum of Space, while not encountering any matter (though rare), has not been verified and likely to lose momentum to lowest frequency and lowest temperature (temperature and momentum of Photon are related at the time of emission and absorption). The Vaccum of Space itself at the lowest temperature will be the next place, beside the matter, for the photon to be absorbed. The CMB is the epoch just before that moment, and where the temperature is approaching 0 Kelvin.
My recent papers for the last 6 months have explored the different independent lines of thinkings, without wanting to prove the alternate source of Redshift theory, have come to the same surprising conclusion.
The Galaxies can also have retrograde movements like planets, where they are moving away and then moving towards.
https://www.nature.com/articles/s41550-019-0906-9