Actually science has all but proved his existence with quantum theory.
This article explains it pretty well while actually dodging the question: https://ninewells.vuletic.com/science/defenders-guide-to-science-and-creationism/big-bang-something-from-nothing/
Basically 'before time existed' there was nothing, but then the universe came into being and there was the singularity, time, and space and then it exploded.