There is not one single verse in the scripture that needs to be spiritualized. There are two kinds of scriptures. One that is direct and means what it says and say what it means. This is most of the Bible. Then there are verses that are imagery and stand for something else.
Revelation 13:1 is a good example of a verse that is imagery.
“And I stood upon the sand of the sea, and saw a beast rise up out of the sea, having seven heads and ten horns, and upon his horns ten crowns, and upon his heads the name of blasphemy.”
I have never seen and am pretty sure that there are no beasts on the earth with seven heads. The meaning was intended to be hidden or not understood until God wants it known for sure. Many have all kinds of ideas about it. Some may be correct, but they are maybe just good guesses.
Romans 9:4 “Who are Israelites; to whom pertaineth the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises;”.
This verse is spiritualized all the time. It does not need to be spiritualized. It is correct as written. What it amounts to is people telling God he was wrong or maybe God changed His mind.
Malachi 3:6 “For I am Yahweh, I change not; therefore ye sons of Jacob are not consumed.”
The main reason people spiritualize verses is to try to make the scripture fit the world they see. This is not how one understands God. Make the world fit the scripture. Then you will understand what God wants you to know. It helps a lot to get the correct people in the correct roles.
It is the World that is upside down, not the Kingdom of God.