So you have no idea why the ancients would have a concept of modern cosmology, right? It's just some baseless notion that rattles around in your head?Your definition of truth involves assuming that a flat Earth is implied. It isn't. Not once.
And yet you have before you thirty examples of their world-view, which incidentally coincides with a fairly general view at that time, as you can check for yourself.
As for a flat earth (to take just two simple examples) both Daniel 4:8 and Matthew 4:10 speak of a height (tree, mountain) from which you can see all parts of the world. The earth can't get much flatter than that.