Well, in all fairness, when you speak of the 8 people supposedly repopulate the Earth after rain for 40 days and 40 nights, I know from experience of living in a place that was borderline Rain Forest, that much rain would definitely cause flooding, but not enough to kill every living thing except 8 people and two of every animal on earth. But let's assume for a moment that it did, and try to determine when that was.
Although there is no mention in the Bible of a specific time or date on which God told Noah to build his Ark, or when the flood happened, the flood is described in the book of Genesis. Jesus talked about the flood in the New Testament, which obviously came later. And if we are to believe that the current year 2025 is 2025 years after Jesus died, then it by simple logic the flood must have been more that 2025 years ago. Thus even if there was "more water than is actually on the earth" back then, certainly doesn't mean it would still be there today. If for no other reason, it could have simply evaporated in all those years.
But that is a biblical discussion that's most likely been done many times, and there has never been an acceptable answer to any of those questions.