The "WHOLE WORLD" to the people who wrote Genesis was a whole lot smaller than the Whole World - They hadn't an inkling about most of the other continants, AFter all, if you sailed too far to sea, you would fall off the edge...there was no North/Central/South America to them, nor Austrailia - as far as they were concerned. They probably had no idea there was a land that would become Englang...etc
In other words, their WHOLE WORLD could flood without it affecting the Whole World
Do you believe in the 5,000 year old earth story too?
What about Jonah spending time inside a whale?
Or are you a literalist only part-time?
"In other words, their WHOLE WORLD could flood without it affecting the Whole World"
Well of course.
But that's not the claim made of (or the burden placed on) the text, by many.