Why does believing the rest of the Bible hinge on a literal interpretation of Genesis 1 & 2?
As stated earlier, it sounds like you are hinging your entire faith on scientific knowledge being wrong. That just seems very odd to me.
I understand that with your world-view you would find a literal interpretation of Genesis 1 and 2 would be hard to accept.
We know that Moses wrote Genesis. If he believed that God created the universe over millions of years through evolution, he would have used the word "evolved" in his description of the creation. Also, he would have made it quite clear that the 'days' described would be longer than the 24 hours between the 'morning' and 'evening' in his description. But Moses has led us to believe that God actually created the universe in six 24 hour days. So, either he misinterpreted what was revealed to him, or that he made it up (in other words, lied about it).
But that would open up a can of worms, because what Moses wrote was the foundation of the Jewish faith, and if he lied at the beginning of Genesis, then the whole narrative of Genesis, including Noah, Abraham, Isaac and Jacob would also be fiction.
Therefore, when God announced Himself as "The God of Abraham, Isaac and Jacob" then He would be either mistaken or lying as well!
Then we would have to cast doubt on all the rest of the Jewish historical books, which form the basis of Jewish history from the time of the Exodus, Joshua, through the Judges, 1&2 Kings, and 1&2 Chronicles, saying that they are not accurate history but works of fiction. But then that would cause problems, because there is abundant evidence that the people and places described in the history actually existed.
Then we have the problem explaining Bible prophecy - how that the bulk of the prophecies of Daniel, Isaiah, Jeremiah, Ezekiel actually came to pass according to the actual subsequent secular history and archaeological evidence. A prominent mathematician calculated the odds of all those prophecies actually coming to pass by chance, and his results were 1:5,000,000.
So, we have to conclude that all of the Bible is literally true, or none of it is. Our only alternative to it would be that it is a set of religious fairy tales designed to help us know how to live self-improved moral lives and until we die and go into oblivion.