Reincarnation allows for more lives, just not simultaneously.

From the moment of the Big Bang onward, science is full of knowledge, ever expanding, like the Universe. Prior to the Big Bang, there is no knowledge of what went Bang. Going by Newton's law that energy can neither be created or destroyed, all this, the Universe, was somewhere, somehow, just not in its present form.

Everything in this Universe stems from the Big Bang, a one off event, containing all that is present in the Universe, regardless as to how many presentations and permutations it may present. It is still one form presented as many. You are confusing separateness, the appearance, as being the reality.

God for me is a title, like general, emperor, or ayatollah. It is what is meant by that title that needs to be explored, religion serves as a boat to do so, once one has a glimpse or understanding, religion is a drag, like keeping training wheels on a bike, once one has learned to ride. It has its place but only as a means to an end, not the end itself.