You keep coming back to entropy, but I think this is the wrong way to look at it.

I keep coming back to entropy because the asymmetry in entropy is one of the things that needs explaining, and because some of the other things that need explaining seem to be explicable in terms of entropy.

[...] when we don't have all the information; but the universe does

Given any criterion for distinguishing macrostates, you can (in principle) compute entropy relative to that criterion. E.g., if you care only about macroscopic thermodynamic parameters when distinguishing macrostates, you get the classical Boltzmann entropy. These parameters presumably stop making sense when you consider the early enough universe, but we can still say that the thermodynamic entropy of the universe appears to be surprisingly small early on and much larger later on.

(If the universe is infinite in extent, there are some technical difficulties here. I don't know exactly how they are addressed, but I note that cosmologists who accept the possibility that the universe may be infinite don't thereupon seem to stop talking about entropy, and I infer that the current best way of addressing them doesn't make the time asymmetry of entropy go away. If there are experts in the field reading this who would like to enlighten me further, I'm all ears.)

once you have identified a microlevel asymmetry [...] there is no need to go through the tedious steps of finding how it produces a macrolevel asymmetry.

I'm pretty sure this is just plain wrong, unless you have already established that the microlevel asymmetry is responsible for the macrolevel asymmetry. So far as I am aware, there is no reason to think that weak parity violation is responsible for the familiar macro-scale time asymmetries everyone notices.