I'm going to boil that down to two questions you seem to be conflating.
WHY and WHAT? Why can mean a number of things, why does water freeze, is a fundamentally different question than why does the universe exist. What is water is a different question still. "Science" does not attempt to define ANYTHING that isn't falsifiable, because if you can't disprove it, you can't ever prove it either.
Science, has absolutely nothing to say about religious whats and metaphorical whys - it can only be used to define, the corporeal whats, and observational whys.
If you actually want to approach the metaphysical logically (and really who really wants to do that?) you have to start by questioning the assumptions first. So the first why isn't why is there a universe, it's why must there be a why, not what created god but what is god?
On this board we overwhelmingly just assume Judeo-Christian mythology, but there are a thousand other definitions of "god" before you ever get to WHAT created God.
Will there ever be an answer? Who knows, certainly when the idea that tiny germs caused disease became accepted, subatomic theory was absolutely unimaginable.
My personal feeling is that the one commonality of religion and science is that they are both born of human curiosity, both tools used to understand the universe, If I trust science, it's because science grants us millions of large and small miracles every day, and I can't remember the last time someone rose from the dead.
I do have faith in science!!!!
