Despite an infinitely hot start and matter forming at well over 3,000 K, the hottest area we have seen at such distances is about 10.K. Most of it is at 2.7K, the same as space away from stars in our neighbourhood, the same as Eddington said would be produced by starlight alone 85 years ago.
As starlight is endemic to an old universe, so microwaves are too. I have been reliably informed that stars produce microwaves.
And what is space that it can be stretched from quantum size to over a hundred billion light years across without being changed in any way? This is just another IDEA as we have no evidence that space can be stretched in any way, or even what it is. Like DM, it does whatever is required of it and that is all that is needed as far as some people are concerned.
As I have already said, redshifted photons can be explained away.
SMBH's were said not to form till 1,400 million years after the BB but we have discovered them at 770 million years, a two billion solar mass quasar) and better technology may find them a lot closer.
We have discovered galaxies at just 300 million years after the BB.
Time dilation only works out to six billion light years away so is an unknown effect which is not consistent with the BB which goes out to 13.7 billion light years away.
The BB failed the afterglow test, with 3 out of 4 galaxies looking like they were behind the CMB.
We have voids of 3,500 light years, whole walls of hundreds of millions of galaxies and so on which show the universe is anything but smooth.
We have the dark flow which shows objects moving at a uniform rate (so not a hidden SMBH) into an area a billion light years across, so the opposite of expansion is happening there.
And so on.
Perhaps you would like to answer these points without just pointing to the wikipedia or it's ilk, and explain why it is true? Excuse me if I do not wait for an answer in this life as I do not have too many decades to go.