Many cosmologists have issues with a singularity of space and time (maybe you will be surprised by this). Indeed the singularity comes about by "running the expansion backwards" based solely on gravity.
But as I've been saying
this is how it got started
and since there are other forces at play
not included in the original equation
the circumstances described in that equation
couldn't have existed and made a singularity
see my post
When Schwarzschild, a 42-year-old mathematician who was in charge of a German military weather station, read Einstein's new theory, which was published in 1916, he used it to make some calculations of his own. Schwarzschild found that if you squeezed enough mass into a small enough volume, its gravity would become almost infinitely strong. It would warp the space around it so strongly that nothing could escape from it -- not even light. In essence, the object would be invisible to the outside universe: matter and energy could fall into it, but nothing could come back out.
Schwarzschild's calculations provided the scientific basis for the concept of black holes.
and since this "scientific basis" is incorrect
why continue to assume the premise is correct?
no singularities, no black holes, no big bang
maybe science has given way to writing for Marvel Comics
The Science of Imagination
The evolution of our thinking about black holes is an evolution of both science and imagination