Hi Robert, we can’t describe how anything came into existence because we don’t really experience anything coming into existence. We observe things and the changes that happen to them.
Our knowledge of the beginning of the Universe or the Big Bang are all established by reverse-engineering of current measurements not by description of observed reality. Asking what happened or existed prior to the start of the Universe is a process of our imaginations, making stuff up. If we can’t observe something, then we cannot describe it. Asking whether the beginning of the Universe was random or not, or determined or not is simply making logical sounding statements about something we do not or did not experience, I.e., more making stuff up. IMO, of course.
If folks think that it is fun, then, well alright, but I suggest don’t take complete speculation so seriously.