There be a few or many others, and I will offer here two hypotheses. First, the less likely, but as far as I can see, it already seems more logical that the official theory, forgive my insolence, which is, for its part, full of imaginary bandages and patches.
What can modify the frequency of the light absorption otherwise? Snow is white because the material reflect all the light it receives. Black material absorbs the light completely (at least all the visible light, it can reflect waves with less or more energy). Your red sofa is coated with a material whose characteristic is that it absorbs the purple, blue, green and yellow light frequencies but not the red one.
So why not a filter? This is an already observed phenomenon as there are many obscure or dark nebulae in our own galaxy. These are the sunglasses of space. If you were near a dark nebula, or even in one of them, you would receive very little light or wave from the outside. What is observed as cosmic background radiation may be a giant nebula which let pierce the microwave photons coming from the space outside of it. Maybe the universe as we know it is in a nebula… The redshift will be explained by the same phenomenon: the part of the nebula on our side absorbs frequencies above the visible red. In fact we see the contours of the dark nebula in which the interstellar absorption is much higher than previously calculated. Quite simply.
No Big Bang, no hot gamma rays and thus no expansion and cooling, and expansion again, and bizarre calculations of energy losses, (possible or impossible)? None of this, but an infinite universe.
There would be no odd acceleration of the expansion of the universe, and therefore no dark energy, which is supposed to be 74% of the universe today, because we can not explain this mathematical huge hole otherwise than by a x and unknown hypothetical material the fact that apparently this redshift are now changing (in fact it would simply be the movement of our nebula).