No, it would validate history. If the event happened, it happened. The bible says the flood killed everyone except Noah's family, which means everyone is descended from them, so you would expect the story to pass down through the various languages and nations that sprang from them.
And if you believe that the flood was widespread but local, like for example the Black Sea region or the Persian Gulf region, it still obviously was a tremendous cataclysm that other nations would have heard of, and would have themselves been affected by. So again, you would expect the story to be embedded in the mythology of many nations in that region.
Remember, the Israelites didn't exist as a people until after Abraham, who was Sumerian. His tribe was gathered from other Sumerians and from among Canaanites.
If the cataclysm was caused by something world-wide, you would expect to see something similar even in mythologies of nations on the other side of the globe, and indeed you do.
Uh, how so? The wicked were all destroyed by God in The Flood....weren't they?