Why did God create us and put us here on earth? I don’t know, but it’s obvious we’re in some sort of school.
We have to learn certain things, say, how to love. Easy to love God, he’s so great. Hard to love our nasty neighbors, especially when they are mean to us. Christianity has been trying for 2000 years to help us learn to love those neighbors. Belief in Jesus is supposed to make it easier. After we die we find out if we did okay or not.
I have often wondered if this was a sort of academy in some sense.