On Thursday, 2 November 2017 03:39:27 UTC+1, Phillip Helbig wrote:

We know that the universe is approximately flat. Assuming a simple
topology, that means that it is either infinite or very much larger
than the particle horizon (the theoretical limit of how far we can
see; in practice that limit is essentially the last scattering surface
[which is operationally defined as the surface at which the universe
becomes optically thick]). So, essentially all astronomers in the
world agree that there are more galaxies than we can see, even more
than we could see with arbitrarily powerful instruments.

I do not fully agree with your argumentation.
When you want to understand what we can observe you have to use the
friedmann equations.
To see the results select:
http://users.telenet.be/nicvroom/friedmann's%20equation%20L=0.01155.htm
In Figure 1B it is the blue line what we can see/observe.
The black line is the maximum distance of the Universe as the result
of the Big Bang. I expect this is the particle/radiation limit.
At present the size of the Universe is roughly 35 bly.
From this simulation the claim that the expansion of the universe
undergoes acceleration is arbitrary.
The blue line (of what we can see at present) starts approx 300000 y
after the BB (See Figure 1C) and reaches it furtest distance 5 by
after the BB.
The blue line shows what we see of the Universe in the past
i.e. in some sense all the present day galaxies in the past.

This also means that if you have a more powerfull instrument
you can not see more galaxies but only the same galaxies (in the past)
more accurate.
With a more powerfull instrument you can see younger galaxies.
They are not further away (at that time) but at closer distance.

Nicolaas Vroom

[[Mod. note -- If you have a more sensitive instrument you can see
*fainter* galaxies at any given distance. Since there are a lot more
faint galaxies than bright galaxies in any given volume of space,
this means that you overall see more galaxies even within the same
volume of space.
-- jt]]