I was most specific: "A global flood 4350 years ago."
Comets and meteors 65 million years ago do not apply. Neither does the Cambrian 500+ million years ago.
All it takes to rule out a global flood at 4350 years ago is something that persists across that time period. That can be DNA, culture (Egypt), soil layers, fauna and flora, etc.
There are many cases where there is continuity across the 4350 time period. As far as science is concerned, this disproves a global flood at that time period. (The early geologists seeking to prove the flood gave up about 1830.)
Genesis does not say that everything was wiped out in the flood. Au contraire, it says all species were preserved. So the "continuity argument" is really a strawman....