I agree with what you wrote. And, I especially agree that since we are forgetting Heisenberg, the discussion is purely hypothetical.
Now, let's consider the real world where Heisenberg's uncertainty principle definitely holds sway. It's a whole 'nother kettle of fish.
So-called random quantum events early on would cause major large scale differences almost immediately. I presume you are familiar with the butterfly effect.
In the process of crawling to conclusions over my lifetime (I try to avoid jumping), I have given a lot of thought to the old mind-body problem, the apparent conflict between free will and the laws of physics, and the (to me) inexplicable experience of consciousness.
The conclusion I have arrived at which makes the most sense to me is that Heisenberg has identified the 'wiggle room' for consciousness (free will) to act on the physical universe without violating any laws of physics. So free will can have only a teeny tiny influence; it can only affect the outcome of some small number of related quantum events. In order for these small events to trigger any macro events, a very delicate, well designed apparatus is necessary.
The Schroedinger's cat experimental apparatus is one example. In this apparatus, a single well-timed quantum event can make the difference between a live cat and a dead cat.
Another such apparatus is a living brain. The mechanism as to how a so-called random quantum event can trigger a specific pattern of neuron firings is as yet unknown. But at least Roger Penrose and Evan Harris Walker have proposed credible mechanisms.
The next piece of the puzzle is this mysterious consciousness with its so-called free will. Is there such a thing? Well, a lot of people have thought so over the centuries, and I, personally, experience the perception, or at least the illusion, that I have such a power. So its existence seems a good bet to me.
The last piece of the puzzle is the question of whether or not some conscious, free-will-possessing agent actually deliberately controls Einstein's "hidden variables" so as to cause specific so-called random quantum events to occur (so they are really not random at all), thereby triggering macro events in our physical universe. Good question.
If the answer is no, then you are right: free will is an illusion, consciousness is an illusion, and the evolution of the universe is meaningless. But it leaves me with the mystery of my own conscious experience which I strongly doubt can be explained away by any argument, and it still leaves the mystery of the ultimate origin of everything. It also leaves me doubting that there was enough time in our history for evolution to have produced what it has. (You have already heard my reasons for this doubt.)
If the answer is yes, then at least in broad outlines, all the important mysteries are solved, except for the one original consciousness that started it all.
So, if the answer is yes, there are fewer mysteries and unanswered questions. That is sufficient reason for me to accept the proposition as the most likely of any that have been proposed.