And the religious can’t explain how God just always existed.
***********
The explanation is that God exists outside of time. We’re created beings who cannot understand this because we must live in time, but God is not. This makes more sense than the creation creating itself.
All you are doing now is just giving is an unsupported opinion. That’s no explanation of how, which is what you were asking physicists to give you about the Universe. If you’re going to do that, then just say the Universe exists outside of time and has always existed and save yourself a step.