The problem I have with a lot of Big Bang theories is that theoreticians can pretty much say whatever they like, due to the fact that it is impossible to look back to the early Universe.

The normal drill if you want to explore the early World is to get a huge telescope and look at distant objects; a galaxy 20 million light years away gives you an indication if what a galaxy looked like 20 million years ago.

This is impossible in principle for the early universe, as when it was a youngster the Big U was opaque to EM radiation.

This allows theories like inflation (which was invented to fill discrepancies in the Big Bang model) to be put forward, rather than questioning the BB model itself.
This kind of shenanigans (postulating theories that can't be verified) is rife in cosmology.
That's what turned me off it after I got my degree.

Well, that and the math.