Could redshift of photons originating from distant places be explained through their own mass and gravity, rather than expansion of the universe?
I mean, if photons' trajectory can be bent by gravity (as in gravitational lensing) (and in my head gravity=mass=object_or_something) wouldn't photons (according to 3rd Newton's law) attract those objects. If photons attracted something, then they gave it some of their energy. Then they also lost that energy. Then they also red-shifted a bit. The further they have to travel, the more energy they lose and the more red-shifted they get.
Another factor could possibly be gravitational source redshift versus destination blue-shift. For us to see an object from a greater distance, it would have to be more luminous and thus probably more massive. The more massive an object the more energy photons lose while leaving it and the more red-shifted they are. Of course, they would also get blue-shifted as they approach our galaxy / Sun / planet. However, the blue-shift part is a constant for a constant observer, while the redshift part is not.
Another possible factor is if, hypothetically, photons having mass of m=hν/c^2 cannot travel exactly at the speed of c. Thus time DOES flow for them and they decay over very large distance. The decayed part would be (or at least contribute to) cosmic microwave background radiation, hence CMBR would have a pattern and not be perfectly uniform. If this is the case then there should be more CMBR coming form larger filaments and less coming from voids.
Regarding ever accelerating expansion of the universe: if accelerating masses make gravitational waves, wouldn't Big Bang cause tremendous gravitational waves? Since gravitational waves distort spacetime, ripples from Big Bang could currently be causing us to have a limited observable universe. And what if that state is only temporary due to us being in such part of the ripples, with elongation (if we can call it that) currently accelerating towards stretched space hence the space is currently expanding (and accelerating at it too). And maybe in distant future there will be a time window in which we will have view over entirety of universe. Until big bang's gravitational ripples dip us into a hole again.