We have been down this track, but neither you nor I can resolve this with a belief and or, a scientific observation.
Where do, "simpler origins" come from and, "simpler origins" are not simple if they contained the essence of all future outcomes in their seeming simplicity. Simpler origins contained all life and sentience, producing a creature that can manipulate the very natural order it was derived from. Is that not a challenging proposition? Does that not suggest purpose, a will acting on outcome?
If will and purpose are not aspects of our reality you are postulating that absolute nothingness acted as though it had will and purpose, produced astounding order, a universe bound by perfect law, life and sentient life, as if it was god itself. Nothingness has gone on to produced a creature that can alter the very matrix of nature it was born from. How likely is that?
Evolution is a fact, all the beautiful physics that has taken us back to the first moments just after time and matter were born, are a wonder to behold, but they are not causes, they are the contingent effects of other causes.
Occam's razor might suggest that if everything has a cause then something caused it. Perhaps it's an entanglement of definitions regarding what that Cause of causes is that causes all the problems.
In your model of the purely materialistic universe there is no purpose, your life and mine have absolutely no meaning, apart from the meaning you imagine into it by borrowing from religion unbeknownst.
So there is no problem with simple to complex, all the proven outcomes of science, evolution, etc, etc, the debate is purely, purpose and will being the motivation at the essence of all natural order. If it were not there why would nature, which is simply a word describing phenomena we can observe, do anything?
The purpose and will are described in countless reckless ways, and endless ridiculous claims are made about it, but that is just human foible. Nothing does nothing for nothing and because something big happened, replete with boundless order, so something caused it. It is at the essence of all of reality.
