“Why would He “create a setting” which differs from reality?”
What matters is not the back story, but how those INSIDE the story behave and think. God would not force man to believe, so He gives us an out - and some choose to take it.
“Through everything God made, they can clearly see his invisible qualities—his eternal power and divine nature. So they have no excuse for not knowing God.
21 Yes, they knew God, but they wouldn’t worship him as God or even give him thanks. And they began to think up foolish ideas of what God was like. As a result, their minds became dark and confused. 22 Claiming to be wise, they instead became utter fools. 23 And instead of worshiping the glorious, ever-living God, they worshiped idols made to look like mere people and birds and animals and reptiles.
24 So God abandoned them to do whatever shameful things their hearts desired.”
If someone wants to reject God, God will let them go...
Which is incompatible with the idea of a universe created with the appearance of age.
The Bible tells us repeatedly that the heavens declare the glory and the justice of the Lord, and that we can know Him by what He has created. Well then, if He created a universe that has an appearance of immense age according to every scientific and logical test we can put to it, then either a) it is indeed 13.8 billion years old, and that gulf of time demonstrates God's eternality; or b) He is a trickster god who creates illusions for the sake of confounding those seeking the truth rather than a God of truth who cannot lie.
Let's look at it another way: The Bible is a creation of God, but one composed by human authors. The universe is God's direct creation, and no hand but His is responsible for it. If He created the universe so as to so confound honest interpretation by adding a false appearance of age, then on what basis could we assume that the Bible would be any easier to come to a right understanding of?
BenLurkin hit the nail on the head earlier in this thread. When asked if God was incapable of creating a universe with the appearance of age, he responded, "Of course God can do that. But why would He?”
Shalom