I’ve clipped to what I intended to be the key to my comment - I thought.
I don’t claim to understand a significant part of what cosmologists say - I’m math-deprived (too long away from school; when I went back, I didn’t make it through integrals)
I do read Hawking’s “popularizations”, and pay attention to commentary from people like Brin (though I know he’s not active as a scientist any more, he’s equipped to understand and maybe, halfway, translate what those who still do research are saying. Was the Egan story published in Analog?
Not to mention that quantum mechanics applies to subatomic particles, not the creation of spacetime. There is the question of the Big Bang seed being particle-like, but that kind of spacetime singularity is not explained by modern physics at all.