A flood in Sumer comparable to any of these catastrophic Floods you refer to, would have been capable of wiping out the entire population living in the area of man’s first civilization. Thus, I agree that such a flood could be considered evidence fitting the teaching of the New Testament (Jesus Christ, St. Peter, and the Letter to the Hebrews) about Noah’s Flood.
Even if, as far as I know there is no evidence for such a flood, I think it is highly interesting to continue our discussion by making the following assumption:
In Sumer around 3000 BC there was a flood capable of wiping out 200,000-500,000 people living in the area, although the archaeological evidence has not yet brought this fact to light.
For me the important point is that at this time there were 10-14 million Homo sapiens individuals living on the planet outside the flooded region.
Using your words, I would like to state:
The population of 200,000-500,000 people who perished in the flood
By contrast, the 10-14 million Homo sapiens creatures outside the flooded region
At a certain moment at the end of the flood, God made all these Homo sapiens to children of God, “with the crucial understanding that makes us human”, but lacking the original righteousness A&E had when God created them; in other words, these new “children of God” were in state of need of redemption (the same state of Noah and his family shared). Since this very moment each Homo sapiens creature is a human being in the image of God, but needing redemption, as if he were fallen into sin.
Do you agree to this interpretation?