Where did the universe come from? Atheistic origin science has no answer.

[Angrboda]

To whom will He demonstrate this to? Why is there even a need to do this in the first place?

for spiritual beings: angels, human beings, God wished to show his attributes such as justice, forgiveness, mercy, and self-sacrifice for the benefit of another in a concrete form rather than in abstraction.

Now you're just making stuff up. What's your chapter and verse on this?

angels learn the wisdom of God by observing people - the manifold wisdom of God should be made known to the rulers and authorities in the heavenly realms...eph 3
pretaining to salvation - even angels long to look into these things....1 peter

Ephesians 3 states that these matters were made known "dia tēs ekklēsias" or "through the church," not by concrete example in creation. That's an impressive feat of quote mining (and of the bible no less!), but sorry, it doesn't say anything about why God made creation. You made that bit up out of thin air. And I'm not going to read 1 Peter just to find yet another equally unimpressive example of quote mining.