There is no evidence of a global flood. There is evidence of severe flooding in that area, but it doesn't prove the Bible because there were recorded flood stories before Noah (such as Gilgamesh, which contains the oldest known flood story).
That something has been criticized is irrelevant. It's why something is criticized that is important. In the case of Sodom and Gomorrah, even Christian archaeologists have criticized the "finding" of those two cities over some methodological issues, including labeling what they found and assuming to know what it was they found before doing any actual work.
Or, there are others who think they found them somewhere else, but what they found was abandoned, not destroyed.
No, it hasn't. We have traced our lineage back a long ways, but as far back as we can does not lead us to the Tigris and Euphrates, it was well over 100,000 years ago (far outside the frame of Creationism), and we find that we came from Africa, not the Middle East.
If there is no evidence, nothing factual to support a claim, I deny it.