Vera
You might say that every element in the universe is “logically contingent” - meaning that it does not exist “necessarily”, it may not exist. (I had a conversation about logical necessity with Gorgias, but that thread was locked down for some reason.) That is correct, but does not help you. The universe is not an object, it is a collection of objects. However, to try to generalize from the elements to the whole container is a well known logical fallacy, the “fallacy of composition”. It may be that every element in the universe is logically contingent, but from that fact it does not follow that the collection of all those elements - the universe - is also contingent.
There remains a lot that is unexplained when positing an eternal universe.
The point here is what is the better explanation.
Universe - does it have boundaries? If so, what? Do you arbitrarily assign them, are they unknown, unknowable? If it has boundaries, what is “outside of the universe”? What is the demarkation between “universe and non-universe”?
Is it infinite from the past in a sequence of time? If so, how could the universe traverse time to arrive at today?
Where did all the matter and energy and natural laws come from? That’s a lot to just posit as “always existed”. Did everything exist as it is today? Why those natural laws and forces and not others? Why are they constant over an infinite period of time? How do some things show change and decay, when this would be impossible (philosophically) in an infinite time? There is potentiality and infinite time. Over an infinite amount of time, anything that is possible to occur - must necessarily have occurred (definition of possible and impossible). Why hasn’t that occurred? What about the multitude of parts that support a universe/multiverse? Are they also eternal existing infinitely? If not, when could they have arisen over an infinite sequence of time? How did a beginningless universe arrive at the time when it could generate something new? If something happens today, why didn’t it happen an infinite amount of time ago (if anything could actually happen an infinite amount of time from any given point)?
There are a lot more unsolved, unanswered issues with an eternal universe. Sure, you can just posit it and accept all of that ambiguity and often just arbitrary claims about a thing that would have no cause, no reason for existing and no way to know about.
God - does He have boundaries? No. He is non-contingent and therefore does not depend on any external force, space or thing to define His being. He is the source of all Being, Knowledge, Intelligence, Power, and Created things. These come through acts not influenced or determined by anything external to him - so he is non-contingent. His free-will is the creative trigger, so to speak. He created time, so exists outside of time and is therefore not changed by time. His being is not measured sequentially. There is nothing lacking in his being. So, there is no potentiality in Him that is not fully actualilzed or realized. There is no lack in being - therefore no lack in goodness or existence, and therefore no evil.
Sure, this remains a probabilistic argument. The question is whether this is more reasonable than a self-existing but contingent universe.
However, if you wish to use God as the underlying “first cause”, then your “explanation” becomes: “an unknown and unknowable being, using some unimaginable means made it somehow happen”.
Your explaination of an eternal universe is the same. It is unknown and unknowable. What power does it have? How does it exist? We have answers for that with God. Since God is non-contingent first cause, God is the necessary Being from which all other causes exist.
And that would be the antithesis of “explanation”.
The same is true of a multiverse. However, you’d have a blind, unguided, unintelligent, contingent thing - supposedly creating intelligence, order, laws, harmony. Why?
Finally, even if one could “prove” the existence of “first cause”-type of creator, from that there is no “road” to the God of Christianity.
Sure there is. You have a First Cause. Accepting that, you accept a Transcendent Being which is not dependent on any other force, matter, laws or powers. The First Cause is the origin of those things. A non-dependent Being, therefore – cannot be determined by external causes. A Being which is non-determined (by gravity, matter, forces, etc) - acts Freely. An agent that acts Freely is a rational being, a person. That’s Theism.
The free act of creation is an act of communication. It communicates the fullness of Being into contingent creatures. These creatures also have intelligence and free will.
So … the Road to Christianity then appears.
If a Free, non-continent, First Cause – communicates being through Creation of contingent beings with intelligence, what else has this First Cause communicated to contingent reality?
That’s where the road takes us on the discovery and analysis of revealed religion. Thus, Christianity.