>as I don't think evolution is sophisticated enough to make a quantum computer
Well, evolution managed to make something that directly contradicts the 2nd law of thermodynamics, and creates more and more complicated structures (including living creatures as well as their creations), instead of happily dissolving in the Universe.
And this fact alone hasn't been explained yet.
Your claim is simply false.
The 2nd law of thermodynamics says that the total entropy of an isolated system cannot decrease. Earth is not an isolated system, it is an open one (radiating into space), and local decreases in entropy are not only allowed but expected in open systems with energy flow.
Life is no different to inorganic processes such as crystal formation (including snowflakes) or hurricanes in this regard: Organisms decrease internal entropy by exporting more entropy (heat, waste) to their surroundings. The total entropy of Earth + Sun + space still increases.
The entropy of thermal radiation was worked out by Ludwig Boltzmann in 1884. In fairness to you, I suspect most people wildly underestimate the entropy of thermal radiation into space. I mean, why would anyone, room-temperature thermal radiation isn't visible to the human eye, and we lack a sense of scale for how low-energy a single photon is.
Nevertheless, the claim that it "hasn’t been explained" is, at this point, like saying "nobody knows how magnets work".
https://www.sciencesnail.com/science/the-highly-ordered-natu...
This is a bad explanation (or a non-explanation).
1. Why exactly life is attempting to build complex structures? 2. Why exactly life is evolving from primitive replicative molecules to more complex structures (which molecules on themselves are very complicated?) 3. Why and how did these extremely complicated replicative molecules form at all, from much more simple structures, to begin with?
There doesn't need to be a "why?", we just need an absence of a "why not?".
Something as simple as the game of life shows you how highly complex emergent behaviour can emerge from incredibly simple rules.
The relevant molecules are made of very simple pieces that like to stick to each other and the way they stick influences their neighbors. It's very feasible to stumble into a pattern that spreads, and from there all you need is time and luck for those patterns to mutate into better spreaders, often getting more complicated as they do so in competition with other patterns.
These are natural outcomes of evolution, you see the same things pop up very easily with simulated evolution* of even non-organic structures.
* that is, make a design (by any method including literally randomly), replicate it imperfectly m times, sort by "best" according to some fitness function (which for us is something we like, for nature it's just survival to reproductive age), pick best n, mix and match, repeat
The second law of thermodynamics is about closed systems. Living creatures are not closed systems.