I once got in an argument (back when I still did arguments) with an atheist over whether or not our universe was designed. He took the tack that if our universe was designed, then (wait for it) who designed the designer? And if the designer was designed, who designed him?
And so on, and so on.
Now, I'm aware of the classical theist responses to this - about a necessary being, about that which begins to exist versus that which is eternal, etc. But I was arguing this from a kind of Intelligent Design "heavy on the empirical observation primarily" perspective, and leaving most theology aside. So my response was simple: Sure, those are valid questions. Maybe there's an infinite change of designers, maybe the chain terminates somewhere for one reason or another.
But that question is moot for the atheist. If the inference is that our universe is designed, suggesting that there is perhaps an infinite number of designers doesn't make atheism more credible: A single designer responsible for our universe is enough to clear atheism from the table. An infinite number of designers each designing each other's universes doesn't change that.
Granted, this doesn't get one terribly close to the God of Christianity. Ed Feser would say that it doesn't get one even a step closer to that God (at least, not to the God of classical theism.) But I think there's value in the general ID/deistic approach, though it's often mishandled by its loudest advocates.