the Kingdom of God is not on this earth and never will be. The reason the Son of God was defeated on the Earth and crucified, then resurrected to absolve humanity of their sins, is obviously because it was never the intention of the Christian God to establish His Kingdom on this Earth

At least as it’s portrayed in the gospels, Jesus very clearly was establishing the Kingdom of Heaven on Earth. That’s one of Matthew’s central theses: the kingdom of heaven has drawn near (Matt 4:17), we are to pray as Jesus did that God’s will be done on earth as in heaven, and Jesus’ return will see the fulfillment of the kingdom on earth.