A redated post.
In making sense of questions concerning cosmological arguments, I think perhaps an important place to begin is to think through what kind of necessity can be attributed to the physical universe. The physical universe, at least if it is beginningless, can be considered to be factually necessary, and perhaps that concept needs to be clarified. I’d like to see a detailed definition of factual necessity.
Once we get this, we then have to ask if we have good reason to think that a universe that possesses factual necessity is unexplained in some important way that could be overcome by accepting theism. Is there a version of the Principle of Sufficient Reason that is rational to accept that gives us reason to think that a theistic explanation is nevertheless needed?
And then we have to ask what reason we have to suppose that the universe had a beginning. If the universe had a temporal beginning, how does that change the situation?