It’s important to note that the term “Big Bang” was coined in mockery of the theory, by someone who rejected it (Fred Hoyle). The theory simply says there is an ongoing expansion of space, and that the universe must have originated from a much smaller volume of space (not a particular location in space). There are numerous implications of this, including a hot dense early universe that evolved through many stages into what it is now. But there was no “bang” per se that started it. We don’t know what started it.
Interestingly, the medieval mystic Julian of Norwich, in one of her “showings” (visions), was shown something about the size of a hazelnut. She was told that this was all that was created. She asked how something that small could survive, and was told that “it survives because God loveth it.”
The size of a hazelnut? All that was created? How did that turn into this? Could Julian have gotten a vision about the Big Bang without realizing it?