How can you distinguish the literal from the poetic?
Sometimes it is easy and sometimes it is hard.
How can you tell if light is a particle or a wave?
You can't make your mind up on the flood story.
It is not that easy. I think most of it is literal but there is a lot of justified interpretation involved. Still there are many other passages that are easy to interpret.
What about the virgin birth.
My personal thoughts do not change reality. It was what it was. I think it was literal. So what?
Resurrection
Walking on water.
Turning water into wine
I think literal. They are called miracles. The claim for miracles does not disqualify them as being true. Unless one has an anti-supernatural bias and relies on tautolgical or circular arguments
We have to use our minds the best we can. Just like we evalauate the evidence in science to sort out the good evidence from the bad.