A great flood is referenced in a number of religions and cultures throughout the world. It most likely was not a localized event.
Christ referred to Noah in Matthew (twice) as a person, Noah is listed in Luke’s genealogy, Noah is mentioned in Hebrews as an example of great faith, and Peter mentions Noah in both of his letters. So to deny the existence of a great flood is to deny what other cultures have reported, what Christ had to say, and what other writers in the New Testament confirms. So I’m not sure how you can make the statement that you follow the New Testament.
Life does not evolve. It devoles.
There is a good chance that a few thousand years after the last ice age a number of huge inland seas holding back incredible amounts of water were let loose when ice dams broke Sending torrents into the then, much lower oceans all in one incredible flood. It raised the sea levels in a matter of days. In places like the Mediterranean it raised enough to break through the Bosporus and raise the water lever hundreds of feet and sending the torrent down the Tigris and Euphrates valley causing mass death and distruction. It also wiped out costal villages all over the planet.