Science cannot tell us why the Big Bang happened, or what came "before" (an odd term to use, as time came into existence with the Big Bang). There are those who think the singularity was simply the universe that had collapsed in on itself, viewing the universe as having a cycle of expansion and collapse.
My personal view is more in line with yours. I'm simply pointing out that science has no answers to this (yet).
Well cosmology faces severe limitations when it comes to understanding the universe’s beginnings. Though observable evidence is available, in the form of Cosmic Microwave Background Radiation, from the point at which the early universe cooled sufficiently to radiate energy. There is, in other words, empirical evidence to support the speculation.
As to what may have preceded the universe, if questions about that even make sense, there is only speculation (though Roger Penrose has done some mathematical modelling).
What most (only most, it’s never all. Scientific enquiry doesn’t work like that) cosmologists are agreed on, is that our universe, the one we inhabit and scientists are exploring, did have a beginning. The competing Steady State model of a universe infinite into the past - the model Einstein tried to resurrect even though his own equations disproved it - is consigned to the history books.
These are interesting times for the Standard Model though. There have always been anomalies with it; no one has yet seen a dark matter particle, not the hypothetical magnetic monopole, for example. The James Webb telescope is already throwing up a few more, so don’t be too surprised if the cosmology and it’s favoured Big Bang model is subject to a revolutionary paradigm shift as radical as that of the Copernican Revolution.
As for science having no answers, well that opens a philosophical conundrum worthy of a thread of it's own; do the laws of science tell us facts about the world? Many scientists would answer no. But it's wrong to say that science has no empirical evidence to support it's theories of the early universe. The CMBR provides the sort of historical record which archeologists studying ancient civilizations dream of finding.