God states (and repeats–Noah must have been a slow learner [or chronically drunk?]) that the rainbow signifies a promise by God that He will never flood out the whole Earth again.
Others want to define “kind” as inclusively as possible to solve the space problem.
But then incredibly supercharged evolution is required after the Flood to expand each “kind” into the thousands (in some cases) of species belonging to that “kind.” Whatever the solution, 99 % of all species of animals became extinct, either between the time of creation and the Flood, or during the Flood, or immediately thereafter.
One must then wonder about an incredibly inept or wasteful creation in which virtually all animal species were doomed to extinction within a couple thousand years.
Having dared to broach the subject of a God who seems less than omniscient (didn’t He know all this was going to happen ahead of time? Why would God need a lengthy Flood to destroy miscreant humans? Why don’t creationists get all exercised about the murder of those unborn?
Was that mean drunk the best of the human race that God could come up with? If you want to hear some really creative additions to Genesis, ask a young-Earther how there could be no rainbows for a couple thousand years, until after the Flood.
You may get some truly bizarre planetary climate models, involving such things as water soaking up through the ground to keep plants alive (let’s see–if there is so much water underground that it soaks UP to the surface, isn’t that what we call a bog? ), or a “vapor canopy” that watered the Earth with a kind of fog, then fell as the Flood rains.
You won’t see anything around you but air and water.
You can also make your own rainbows with a garden hose in full sunlight–no clouds required at all. Maybe God provided Noah and his family with snorkels ? Or it’s been found too many times, in completely different locations.
Why destroy billions upon billions of other living things? And of course there’s Noah and his kin, who, of all the human race, deserved to survive.