I really don't expect to convince you to agree. All I can do is explain my perspective. Which, by the way, comes from a person who has been a follower of Jesus for many years and is still a follower of him. Now, you may not think I am, but what you may or may not think about my status is unimportant. I make no judgements about you or your faith (1 Corinthians 4:3).
Your quotation from Matthew 12 does not demonstrate Jesus believed Jonah was historical--he referenced a story familiar to his audience.
For instance, I can say, "As inspector Javert could not fathom the concept of grace and killed himself rather than accept the forgiveness Jean Valjean offered, so there are many today who will not accept forgiveness of God." That does not mean I believe Les Miserable is a work of history. It does not mean I believe Javert was a historical inspector.
That Jesus would quote the story of Jonah as a metaphor of what he would experience does not prove that he understood or believed Jonah to be literal history. One does not lead to the other.
The Bible is a collection of various types of literature. Including law codes, narratives, poetry, and theatre (book of Job). Jesus tells parables which are extended metaphors. Are they historical accounts (e.g., was there a real Samaritan Jesus was describing who stopped to care for a Jewish man who was mugged on the road to Jericho? Did the trees really select a bramble to be their king, Judges 9; or a rich farmer who took his neighbor's ewe lamb to prepare for a feast, 2 Samuel 12)?
If Jesus, Nathan, Jotham, et al could use fictive stories to make a point and if God could use a variety of literary genres in the collection of Ancient Near Eastern Literature we call the Bible--then why couldn't he use satire, an extended parable, or even a novel?
Does the book of Jonah actually make the claim that it is history?
For the record, I believe the Bible is exactly what God wanted us to have to reveal to us his desire. But I also believe, to quote you, that God is not limited--he can use any form of literature he wishes in order to express his desire--be it poetry, legal codes, personal letters, historical narrative, or even parabolic stories.
Please, too, in your next reply don't trouble yourself with typing up extended quotes from the Bible. All of my degrees are in biblical text. You can just make a brief reference and I'll know what you're talking about.
By the bye, I know Jesus does not call the fish a whale--neither does the author of the book of Jonah.
I guess what is particularly bothersome in all of this is the missing of the primary point being made by the book of Jonah itself: exclusivism/racism.
Oh, and I'll leave the last word to you.