God didn’t make something out of nothing the way a magician pulls a rabbit from a hat. He created the universe without using preexisting material because, as the first cause, He is not limited by matter, space, or time. Nothing has no properties, so it cannot produce anything on its own, which is why something eternal must exist. The idea of universes begetting universes only pushes the problem back, you still need a first cause that is necessary and eternal. An eternal mind creating without time is not just an opinion, it is the only kind of cause that fits a finite, law-based universe. Once you establish that, the question of which God it is comes from historical evidence, such as the life, death, and resurrection of Jesus