Our location “saw” the CMB light from within the Hubble distance, then only 700,000 light years (today 14.5 billion). But the speed of light does depend on distance and the rate of expansion of the universe.

At the time of CMB radiation, the speed of light approaching us from the distance 42 million light years was

c’ = c - Hd = c - (42 / 0.7)c = -59c.

That is, light from this distance could not approach us, but receded at 59 times “the speed of light.” We see it now only because of the changes in the Hubble distance over the past 13.799 billion years. Here’s the light path:

The CMB matter (black arrow) has today moved out 46.5 billion light years. All this time, the light (from 42 million light years away) moved initially nearly as fast (red line), but as the Hubble parameter diminished over time, after 3.2 billion years, slowed with the diminishing rate of expansion of the universe to flat zero, and then to motion (relative to us) of minimal approach, continuing at speed c’ = c - Hd, where Hd falls from the value c (at 5.8 billion light years) to zero as the light reaches us now, at speed exactly c.