I like this cosmology calculator: https://www.astro.ucla.edu/~wright/CosmoCalc.html Enter redshift z=1100 (which is the observed redshift of the CMB) and hit the “general” button, which calculates the distances using the currently-accepted general model and Hubble parameter/dark matter/dark energy values. This gives the “comoving radial distance” of 45.5 Gly (giga light years). That means that if right now, at this very instant, you put down a meter stick in front of you, and the buddy next to you put down a meter stick, and the buddy next to them, and so on through the next galaxy, and every galaxy, all the way to the place where the CMB in that direction originally came from (the place is still there and there is probably a galaxy there now though there wasn’t one back then), there will be 45 billion light years worth of meter sticks.
The other values of note are the light travel time of 13.72 Gyr (travel time is how distances are usually reported in news articles, as opposed to scientific articles that only report the redshift z), and the age of the universe at the time the light was emitted: 0.37 My = 370000 years, which is the age when recombination happened. The total age of the universe (13.721 Gyr) is the sum of these two.
The value you probably want is the “angular size distance” in the calculator, which is the meter-stick method done in the moment when the light was emitted rather than at the moment right now. In this case the distance is 0.0413 Gly. Only 41 million light years, really close by! There was a lot of stuff packed together, but it has stretched out since. The relationship between the two distances is:
comoving distance = angular-size distance * (z + 1)
So redshift of 1100 means the spacing has been made 1101x times wider.
Of course if the universe were literally stationary then your question wouldn’t make sense because the universe would never cool down and CMB would not happen. If the universe expansion had stopped at the moment the CMB happened, then the distance to the CMB you want is the 13.72 Gly travel time distance, but it wouldn’t be our CMB anymore, it would be some other last scattering surface much farther out away.
I like to imagine the origin of life as some organic scum sloshing around in a tidal wavepool. The evaporation creates concentration, the soapy foam provides compartmentalization. The bubbles merge and break apart, hosting populations of spontaneously-polymerizing goo. With enough time and luck, you get some randomly-formed polymer that is able to catalyze more polymerization. From there natural selection takes over. Sometime later the polymers learn how to stabilize their own bubbles, so they are not at the mercy of the waves any longer. This keeps the other random polymers out, such that when the auto-catalytic polymers catalyze more polymerization, they create more copies of themselves rather than of random junk. This is hugely advantageous to their population numbers, so that if such bubble stabilization can happen at all, it will happen and then dominate.
In this fantasy it is difficult to point to any single bubble and say “This, this is the first cell.” It’s all just a bunch of foam seething, forming and reforming. The polymers keep mixing and separating. To draw a line at one is as arbitrary as to say “This, this is the first chicken, born of an egg, laid by a bird-like creature who is not a chicken” to solve the chicken-and-egg problem. There could be thousands of generations of chicken-like creatures, any one as good a pretender to be the first as another.
There are thousands of bubbles, no single moment of transition between non-life, proto-life, and cellular life, but I do believe they have to come from around the same time and the same wavepool. There isn’t some other wavepool from a hundred million years later that completely independently grew its own bubbles and resulted in a separate line of universal descent that later got merged into the tree of life. It happened on Earth once, so it could have happened again in a hundred million years… EXCEPT that now that it has happened, the existing life would colonize the entire planet and eat up all the organic goo molecules as quickly as they become available. Proto-life cannot outcompete full-life.