We don’t know what existed prior to the big bang, ipso facto we don;t know what if anything science can explain about it, that is axiomatic.
It already does, we already have explanations about the universe that are derived from a species that evolved in it.
Yes I agree theists do seem to think they can make assertions based on appeals to mystery, as your posts attest, but these are argumentum ad ignorantiam fallacies.
No you are making strident assertions about what science can explain about the origins of the universe, when you don’t know what existed prior to the big bang, or what was possible and what not. Even were your strident claims that science cannot explain the origins of the universe accepted for the sake of argument, it still would not evidence any deity, that is a false dichotomy.
To stridently claim the universe cannot always have existed but in some other state, alongside the claim a deity has, is a special pleading fallacy.
It is not sound to create arguments that violate a basic principle of logic, by using known logical fallacies, and labelling them philosophical is meaningless.
Why can’t the universe always have existed in some state?
You again using a special pleading fallacy, and we know the existence of the universe is possible, we do not know that any deity is.