WHY is God the first uncaused cause and why does God not need a cause? Why not simply say "The universe was the first uncaused cause"?
All we can say from the Big Bang is that apparently the Universe started. We don't know why, we don't know what came "before" time.
The Christian philosophers of the Middle Ages were keen to use the logic, reason, and the syllogisms of Plato and Aristotle and put it in the service of Christianity.
Augustine, Abelard, Aquinas were highly educated men who desired to infuse Christianity with a strong measure of reason and logic.