The religious notion of creation still presumes there was a state of nothing in some alleged p before time.
The Big Bang makes for a chronological event horizon, yes, so we can only hypothesize what happened before or if there even was a before, and if there is a prime movement of the cause-effect chain.
God is not an answer. At very best, it is a label with no established properties. Especially not the first-dad properties that religions appoint God (omnescience, omnibenevolence, etc.)
(If you want to argue a simulated universe, then we can start talking about programmers.)
But where Stephen Hawking posited time only started with the Big Bang (so if there are causes, they'd have to occur on a separate, perpendicular axis of time), where Brian Greene (focusing on string theory and brane cosmology) figures ours is a single universe in a vast foam of them in a higher order manifold, and the intersection of two branes can cause a big bang event which is commonplace within this foam.
But what they figure is the universe we live in was started by natural forces, much the way our star was formed, or this earth. Those who are desperate for a creator deity to worship might try to insist They created the bulk (the foam manifold) but that positions all of life on Earth as infinitessimal and incidental. The depths of our own universe are unfathomable, let alone the countless others that exist alongside us.
It's stll a presumption, and if we were to take Hawking's approach (time started with the big bang, ergo, there's no before in which causes could occur) it still leaves no room for a creator agent. Nothing happens without time.
So how does that work? We don't yet know. It remains a singularity in our models.
But just as science is merely a (pretty darned accurate) model of the mechanics of the world we live in, religion is a mythical narrative of that world, based on tradition, and willfully modified to adapt to political, cultural and technological developments. The real world continues on its own and doesn't care what we think... or if we're around to think about it.