i think it’s more likely that the red shift we see from distant galaxies is really due to light slowing down incrementally, which slowing down only applies or is noticeable across very huge distances such as between galaxies. obviously light can move between galaxies, but think of how far apart galaxies are. i don’t believe the speed of light is totally constant, i think it must lose tiny little bits of energy over time. or, the little wave in ether which a photon is, will inevitably end up slowing down and stretching out very very gradually.
physicists say the red shift we see in galaxies is because they are moving away from us at speeds which increase the further away the galaxy is from us. i think that’s stupid. there is no reason why everything would be moving away from everything else at increasing (accelerated) speed. by contrast, the idea that red shift is caused by the vast distances causing light to very gradually stretch out makes way more sense, and also explains why galaxies further away from us are more red shifted than are galaxies closer to us.