What preceded the hot dense soup involves conditions that are a problem for both theory and experiment. For theory, those conditions involve both quantum gravity and general relativity and we don't have any accepted way to resolve those yet. And, for experiment, the hot dense soup is opaque to our observations. There are educated guesses as to what might have come before, and one guess is that it leads back to a singularity, and the popular view of the Big Bang theory is often that singularity as the kickoff, but we don't have anything resembling evidence. And whether anything came "before" even that is super speculation, even the concept of "before" may not apply.
“There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable.
There is another theory which states that this has already happened.” -- Douglas Adams