It doesn't disprove anything. It proves that we have precisely no bloody clue what to think. In the absence of knowledge anything is possible. The bare fact that anything could be outside the universe is testament to the fact that we know nothing about what is outside the universe and nothing more.
"What if the universe was created?" What if? I say: "So what?" Whether or not the universe was created is trivial in the grand scheme of things. It is only ultimately relevant IF and Only IF the universe is the entirety of Reality. If there is Nothing outside of the universe; no parallel universes, no alternate planes of existence, no quantum duplications, no membrane hyperdimensions, no anything, then the universe is self-contained.
Self-contained does NOT prove eternal. How anyone could possibly make that leap of logic is beyond me. Self-contained means that the system isn't dependent upon anything else to perpetuate its existence. But it might still have been created. What if the universe were everything and it was created? Well what then?
You require creation ex nihilo. This is logically impossible as long as identity is in play. This means that you need something outside of reality (vis-a-vis) the universe to explain why there is a universe in the first place. The causal argument of "Well what created this transcendent thing that is responsible for everything" is a non-sequitur. It is absurd to ask anything about that which is outside existence.
As long as you are confining your discussion to Reality, then what created the universe might as well be asking if ET or us from the future or a parallel universe did it. This could all just be a really sophisticated AI program developed by a sentient super race from the 39th dimension.
Additionally exactly how is the possibility of infinite regress proof that there is in fact infinite regress? Yes, there is the distinct possibility that reality is eternal, uncreated, and self-contained. It would rather prefer things if it were, but what evidence do you have other than your own preferences that this is in fact the case. That it requires something which exceeds human conception or experience is Not proof of absence. That the explanation requires absurdity is also not evidence.
In logic systems are allowed to have qualities that their components do not. Reality is allowed to have an endpoint even if nothing within it does, and there isn't anything that can be said or done about this since we don't have any evidence one way or the other.
MTF