I don't have any time left but let me clarify something.
I have always understood that the "world" that was destroyed was not the earth itself, but rather the "world of mankind". I believe this misunderstanding is what causes some believers to think that God is going to destroy the earth with fire in the future. This is not so, according to my beliefs. The "world or mankind", minus any of those God chooses to spare, will be destroyed but not the earth itself.
I have known for a long time that at that time people did not populate the entire earth. However, when picturing the flood I always pictured people living all over the globe, so out of necessity the "entire earth" had to have been flooded. Sometimes I am so blonde. But a global flood need not be the case if all of mankind was localized.
And I have always accepted that large parts of the Bible are written from the point of view of a human, in this case Noah. So the entire earth as he knew it was destroyed.
So to me the only possible questions left are:
1. How local was the flood? Was the "world of mankind" really destroyed in it's entirety?
2. Did Noah have anvance warning?
3. Did Noah build an ark and survive it?
4. Did all the flood myths originate from an original? If so then is the Bible's version accurate.
What was the "watery deep"? I've often asked this question to myself and I never could figure it out, and didn't really do any research on the matter. But now I am reasonbly sure it referred to either a tsunami or the sea. And I think most likely the latter, or even a combination of the two.