Becoming like God is pretty much a central tenet of Christianity

No, that's not a central tenet of Christianity at all. From the Catechism of the Catholic Church -

Between God and us there is an immeasurable inequality, for we have received everything from him, our Creator. The merit of man before God in the Christian life arises from the fact that God has freely chosen to associate man with the work of his grace. the fatherly action of God is first on his own initiative, and then follows man's free acting through his collaboration, so that the merit of good works is to be attributed in the first place to the grace of God, then to the faithful.