I think what we are missing here are a couple of three things. First, is there anything impossible for GOD. God can do anything He pleases. He speaks and dry land appears. He forms and animals and humans are made. If we look at God from a human perspective, meaning with our own intellect and understanding it seems impossible. There are many such things in the bible. Even Moses said to the Lord, even of we kill all of our livestock, it would not this multitude for one day. The Lord answered, do you not think that I can prepare a table in the wilderness. He feed them for 40 years. There is nothing impossible for God.
Secondly, We see in this account, That God had determined to destroy humanity. Yet, He found Noah faithful and provided an escape for him and his family. Also, the bible says, that the whole creation yearns for redemption. So he even provided escape for His innocent creation.
Thirdly, what was the ark made of. Wood. Any time we see wood in the OT, it is symbolic of the work of Christ. Cursed is a man who hangs on a tree. What did Moses staff turn into and with what did he strike the rock with from which water came forth in the desert. When they were tormented by fiery serpents, what did theylook upon to be healed, a snake on a pole ( Christ). When Elijah was building a school for the prophets and the young one lost the axe head in the river, and said als master for it was borrowed ( that's a debt he could not pay). Elijah said, throw the hanlde in the river (wood) and the axe head did float.
It is mainly about Christ. However the account is true, if we believe that God can move mountains in a stroke.
May be some typo's but that's my thoughts.