@nicolaou
You are right in one sense that it is a myth. But if it is a myth, then they are not scientifically verifiable claims. Then it's problematic to have an argument with those statements.
On the other hand, if the author(s) of Genesis were working with the idea that Creation or the Flood was God's work, that God Almighty was behind it, then they didn't have to go into the details that we would welcome today. Example: the Hebrew "yom" => "day" appears about 2500 times in the Hebrew Bible. It has a wide semantic range, so "yom" can mean a few hours out of a 24 hour day (the light part of the day), up to an indefinite period of time e.g. in eschatological statements about Yahweh's day...
Creation in 6 days, then, could have lasted 24 hours, or thousands of years, or at the beginning of billions of years, and in the last day, maybe only 12 hours. Similarly, the flood of the world: passages from e.g. Genesis 7 speak of a planet-wide flood, but the text from Gen 2:10-14 suggests that the Euphrates River, for example, was re-identifiable after the flood, that its bed or direction of flow did not change. This raises the question of how big the flood was and what part of the planet it flooded, and what happened on the rest of the planet if it was a regional flood... to one who sees God behind the events, these details are irrelevant: the flood happened as described, and if the flood happened only as a local event, then it does not change the Bible's account. The really tricky part is the question of God's justice (why there was a flood in the first place, and why life went on)...
But of course science cannot consider the influence of God on world events. Especially natural sciences are based on experiment and if such experiment is not possible (astrophysics), then there are theoretical models that are then tested. Scientific theories are then supposed to be open to falsification (and in human terms, verification), so science itself affirms that it is not, does not want to be, and is not meant to be dogmatic. And rightly so.
The conflict between the Bible and science, then, is resolved by believers more or less well, by the person of God.
Personally, I think the arguments against, or more accurately: the arguments that do not affirm Creation, are very rational, indeed most scientists, adhere to the principles of the philosophy of science, theories of truth, etc. The competing model that the Bible describes is only slightly better. The very small, slight difference, is made up precisely because God is behind it. A biblical, religious text, without God, will not stand up to science. It becomes a myth, a legend. But this, on the other hand, says that against such a myth, serious science does not have to define itself. Science does not criticize, for example, the cosmogonic ideas of Hesiod in his Theogonies...