Quantum systems have much nicer properties from this point of view. An internally entangled quntum state can be an ontologically basic entity while still possessing a rich internal structure, in a way that has no direct equivalents in classical physics

That makes some sense, although I don't see why a classical simulation of the same wouldn't feel identical.

Models of quantum computation are quite variable in how resistant they are to decoherence. Topological quantum computing is much more resistant to errors than models based on ordinary quantum particles.

This may be true in the same sense that sending a probe to Betelgeuse is easier than sending a probe to the Andromeda galaxy. You are still talking about fantastically difficult things to keep in coherence. We're still talking about systems kept below at most 5 kelvin or so (being generous). It is noteworthy that so far we've actually had far more success implementing standard quantum computers than we have with topological quantum computers.

Why wouldn't there be? Intelligent processing clearly confers some evolutionary advantage, and there have been many proposals for artificial general intelligence (AGI) using quantum computation.

There's no evidence of any process we associate as part of "intelligence" as being sped-up or made more efficient by quantum computation. I'd also be very interested in seeing citations for the claim that there are "many proposals for artificial general intelligence (AGI) using quantum computation."