ICANT writes:
At the present there is no scientific THEORY of how the universe began to exist. There are several guesses but there is nothing that reaches a consensus.
That means that the existence of the universe can not be explained by science.
The second sentence does not follow from the first.
There are many historical discoveries where there was a time with no scientific THEORY of how a thing worked, there were several guesses but there was nothing that reached a consensus.
Then new information came along, and a scientific theory was developed and a scientific explanation was accepted.
It's quite possible that we simply do not have the information available to us now but at some point in the future we could obtain information that allows for a scientific explanation of the existence of the universe.
It's not valid to say something can never be known just because it's not known right now.
Perhaps it can be explained by science, and we just don't know how to do that right now.
The only way the existence of the universe can be explained so far is by the uncaused cause mentioned in the OP.
I wouldn't call that an explanation.
I would simply say that the existence of the universe is currently unexplained.