Atheist is almost never a superior position.
Almost all theories of the universe you can throw out to supplant god falls prey to the regress paradox.
For the sake of this thread I will lay out the 5 most common creation explanations. For the god option we are going with Catholicism circa 1920's, and Father Georges Lemaître. All options assume big bang/cosmic inflation happened.
1. God (The Christian Science Monitor God)
2. Repeating cycles, no end nor beginning
3. Vacuum Genesis
4. Cosmic Brane Collision
5. Budded of from Another Universe
From there it is an assortment of cyclical models (even after 'dark energy' was proposed), every variation of multiverse splitting, every option has a place somewhere in things which still fall behind the Christian and Hindus in terms of popularity.
From three and on you will take you to another reset of things that need explaining. For the zero-energy universe or vacuum genesis you still need the absolute vacuum for this speck to rise from.
In the end, no matter what you do, whatever cosmological idea you can come up with, there is an; "infinite total vacuum", "hyperspace bulk of branes", or "sea of soap bubble universes, sometimes independant, sometimes splitting off" to explain away.
The point of all this being, no creation theory gives you the proto form, or you are left assuming any number of new features must have always existed, or the product of something else. You give yourself one more thing to explain away..
Its hard for an atheist to find an answer not contrived. It is hard to not incorporate a like placeholder in a like way. God is supplanted for a contemporary and may the new feature in your explanation to explain away god sit at a table with god. Especially if you cross an argument for god as the Alpha and The Omega Less Than The Value of One.
"I am so done with this one, let's just get this the fuck over with".
It is for this reason I must surmise the only path for an atheist to take, and have integrity doing, is to hold cyclical model. A view of universal oroboros. The universe that's tail eating snake existence is the humorous way out of the regress paradox of its creation.
In short: The only way for an atheist to have integrity in an argument against blind belief is to hold the same creation belief as a Hindu.