I have long believed and teach that pretty much every ancient culture has its own flood story(ies). But the fact is that floods occur all over the world. And if you are an ancient one without benefit of books, extensive travel, radio, television, reports from outside your society, and you see flood waters extending as far as you can see in every direction, you likely would believe the flood covered the entire world. And would record your impression of that.
I resist trying to stretch the fossil record to conform to our literal 21st Century interpretations of the Biblical texts however much I appreciate and believe the Bible. For instance, I live near a 10,000+ foot mountain, and on top of it there are sea fossils clearly visible in the rocks along several foot paths.
The Bible literalists say that is proof positive of a universal flood as the Bible describes. Those of us who know science however go with the scientific opinion that this area was once a vast shallow sea and that relatively young mountain was pushed up out of that sea (along with the rest of our state) by seismic activity and shifting of minor tectonic plates roughly 10 million years ago.
I respect both beliefs but I can only go with one of them.