These aren’t assumptions about the text. It is not an assumption that the Hebrew words can be translated mountains or hills and earth or land. It is not an assumption that the text actually says the water rose 15 cubits and covered the high hills/mountains. It is not an assumption that the Hebrew text says the ark landed on hills (plural), not a particular mountain.
Did you look at the NET Bible notes?
And if you want to look at the evidence that God has given us in creation, look at the diversity of animals around the world. There are thousands of examples, but start with the dodo bird. How did the flightless, slow bird move from the ark 5000 years ago to an island in the Indian Ocean and nowhere else?
God has given us the example of the dodo bird, perhaps so we won’t insist the early chapters of Genesis are literal history. The scriptures also give us two creation stories with different orders and methods of creation, perhaps so we won’t insist the early chapters of Genesis are literal history.
I know it takes time to realize the things you were taught may not be right, it did for me. But we need to move past the teachings of childhood and into a fuller understanding of God.
One of the things that helped me understand the way the ancient Hebrews were willing to share stories that had wonderful pictures and truths was the story of David’s rescue from Saul. The actual events are described, with David avoiding the spear thrown, hiding with the Philistines, sparing Saul in a cave.
And then there is their second version—with God flying down on a cherub hurling lightning bolts with smoke pouring from his nostrils (found in Psalms 18 and 2 Samuel 22). The second version is not untrue, and it is not literal history.
Thomas, going back to making assumptions: you and the video are making a huge assumption: that the story is a lie if it is not literal history.
Jesus told a story about a Good Samaritan. He never said “this is a story, not literal history.” He wasn’t teaching history, he was giving spiritual guidance.