Or the actual galaxies whose images we see at the edge of our visible space are much further away than they appear, and only the images are visible due to some optical distortion. Here is why....

Imagine hovering over a black hole event horizon in a spaceship. If you could maintain your altitude close to the event horizon, time would slow down. Events elsewhere in the universe would appear to speed up, including the rate of infalling matter. As the rate of infalling matter increases the rate of growth of the black hole would increase as well, moving the event horizon outward and eventually overtaking your spaceship, slowing time down more as it approaches, in a self-reinforcing accelerating progression. As you touch the event horizon, time dilation becomes infinite, the rate of infalling matter becomes infinite, and the rate of expansion of the black hole exceeds the speed of light. The event horizon goes superluminal and shoots across the entire universe in an instant.

In reality no spaceship could hold its position. No matter how powerful its engines, it would fall into the event horizon because the event horizon would overtake it by sheer speed. IMO the two scenarios have to be reconciled somehow. For the spaceship the whole universe would appear to be pulled inward towards the event horizon as time was dilated. Then, when the event horizon washes over, the whole universe would appear to be squashed onto the surface of that sphere. An instant later those same images might reverse direction, and move back to their original positions, with some sort of relativistic distortion. Hence the cosmological redshift. The question on my mind is whether those distant galaxies are where they appear to be, or are we merely seeing an optical after-effect similar to the "Einstein Ring" from a gravitational lens.

There is no doubt in my mind what is causing the cosmological redshift. If we could observe the whole universe instantly without any time delay, we would observe the accelerating geometric growth depicted by my Black Hole Inflation simulator. But since we are limited to photons, IMO we are seeing a relativistic effect. How that effect occurs is very difficult to imagine intuitively, especially since the rate of time would be different between separate regions of space.