The answer depends entirely upon one’s definition of God.
If God is defined to be a logic limited entity bound by at least one law of physics, one can legitimately invent interesting answers to the question of purpose.
However, if God is defined as the omnipotent, omniscient God of Christianity and derivative religions, all answers to your question are simply the result of human imagination, and equally absurd.
By way of analogy, consider…
The difference between your IQ and that of your pet gerbil is large, but finite. The difference between your IQ and that of an omniscient God is infinite.
Imagine reading a story with a complex and mysterious plot, such as a classic Sherlock Holmes mystery. Read it out loud so that your pet gerbil can hear. But read only the first sentence, to make the amount of story disclosed to the gerbil equivalent to the amount of knowledge about the universe owned by mankind.
It is far more likely that your gerbil will figure out the Sherlock Holmes plot after you’ve read the first sentence of the story to it, than any human will ever understand the purpose of an infinite God.
So why ask the folks on CAF? With respect to such questions, they only know what they’ve been instructed by the Church. You don’t need to post a thread for this— you need to buy a Catholic Catechism.
A limited-God concept offers more interesting possibilities.