This is about the most basic logical fallacy. "You either give me an explanation, or you accept mine regardless of its merits".
You twist the meaning of open-mindedness to serve your belief. I am very open minded. I don't think I hold the same opinion I held 5 years ago on the majority of subjects. Does that mean every sentence uttered as divine truth is worth considering? No.
There are many MANY possible explanation of how the universe came to be. Most of them are far superior to "it was created by a supernatural being". Hell, if that is a reasonable hypothesis, then I can make them up on the fly. The Blackswordsman created the universe. His denial only confirms it, for Lord TBS is most humble. Please keep an open mind about my "theory".
If we're going to discuss your god, you must define him. You must do it in real terms, with real meaning, because that shows you know what you believe, and not just parroting empty statements like "god is forever". Then we can discuss whether that construct can possibly come from nothing, and whether it can create universes.
Until then, we can contemplate other ,better, theories:
Quantum fluctuation:
https://abyss.uoregon.edu/~js/ast123/lectures/lec17.html
This one denies the universe is something at all. The number zero can be thought of as a representation of nothing. But it can also be made up by somethings. -1+1=0. Similarly, the universe can just be a temporary blip of somethingness over its natural state of nothingness.
Simulation:
https://inspirehep.net/record/1189720
If humanity survive long enough, it is reasonable to assume that computer simulations will become sophisticated enough, that universes with different parameters can be produced. Some of those will in turn produce conscious beings, who will wonder about the nature of their universe.
Multiverse:
https://www.scientificamerican.com/...cations-lend-support-to-multiverse-hypothesis
This is by far the most scientifically supported possibility. The universe is part of an infinite number of universes that flux in and out of existence. They have no beginning and no end, collectively. And there are many others. SO MANY. But until we have the ability to test such hypotheses, they remain in the realm of amusing speculation.
Edit: If this is hijacking Whisky's thread, I'm willing to take it elsewhere.