The theme of the Bible isn’t to answer every question in the universe. It gives the Crib note version to lay the groundwork. “In the beginning….” It doesn’t say when the the beginning was, but the translation of the Hebrew is “dateless past”.
Where do people get the idea that the Bible promotes a flat earth? Scripture says, “He sits enthroned above the circle of the earth”
Isaiah 40:22

"I was born in the log cabin I helped my grandfather build"