One reason why it is nearly impossible to examine the bible using scientific methods is that the Bible is not a science book. Unlike a story which flows from beginning to climax and ultimately to conclusion, the Bible jumps around in time and does not always follow to a logical conclusion. Every verse is important, but sometimes it is hard to connect them together.
What do Young Earth, Gap Theory, and Day/Age creationists all have in common? They all believe that in the beginning God created everything out of nothing. And they are all rabid anti-evolutionists. Being against something that you do not understand does not make you spiritual or smart.
There were Nephilim before and after the Flood. If the flood was to destroy evil people, how did these creatures survive? Nephilim are the offspring of angelic sex with human women. A local rather than a world-wide flood would make this possible. Nephilim were very smart as well as very big. A few could have survived a regional flood event.
Evolution is anathema to Bible believing Christians. But it does explain some things that the Bible does not explain at all.
The earth in Genesis 1:2 was shapeless and empty. What was it? A watery mass, A sphere of liquid water in frozen outer space? The Bible is not a science book at all.
One day hopefully we will understand all the mysteries of the Biblical narrative.