Everything in creation testifies of God’s glory and goodness every day. From the giant Sequoia trees to the smallest moss on the ground and the Blue whale in the ocean to the krill that it eats for food, God is glorified because of the diverse and wonderful differences that we can see in our world. When you look at the heavens through a telescope and see the Orion nebula or the Pleiades in all of their splendor, you are seeing the handiwork of our Creator. Why would God create all of these beautiful and diverse wonders for us to behold?
Because He is God and He enjoys creating and allowing us to enjoy His creation, not for vanity but because it brings wonder and awe into our lives and it makes us wonder about the Mind of God and why He would create all of this. Are there other worlds out there with life on them like us? Maybe but He didn’t give us that answer in His Word, He only tells us what we need to know. If you can’t accept that or you won’t accept it, then I’m sorry. God doesn’t owe you or me an explanation for how He does things.
He is God and there is no other like Him.