That is not my question. My question is whether God used some pre-existing materials to create the Universe. You seem to imply that He did not. So, He made the Universe out of nothing. is that correct?
The problem with infinite regress is the reproduction of the exact same question with every answer in a continual series of infinitely cascading dependencies.
Your question is like what material were used to create the material? The question would keep shifting backwards infinitely. If we agree that beyond the beginning, matter and physical laws were absent, then we can't say, what material were used to create the universe. In this case, The beginning would depend on a cause not prior existence of physical matter.
My question does not imply anything of the sort. Remember, I am a supporter of the block universe theory of time, so I do not really need to tackle with things like causes, beginnings or anything like that. This interpretation of time get rid of all your arguments, at once.
But I am curious. Suppose that I do not invoke it. Just for fun. What is the problem with infinite regress, if any?
The problem with that view (no beginning) is that any point would equally have infinite past/future. In other words, Any point would be exactly equal to any point which implies a static universe. this is not true. Observed progression/ changes necessitate a starting point.
Nonetheless, I always thought About time as a line from A (starting point) to B (end point). Present is a point that can only move forward along the line. Beyond time, all points along the line (past and future) exist, what varies is the location of the present point along the line (spacetime). But as mentioned above, for the present to experience a change, a beginning is required otherwise any point along the line would be equal to any other point. All present points would be exactly the same.
In any case, the block universe theory is not a scientific theory but rather a philosophical approach.