@nekronavt
I believe that when you unwrap a multires sculpt, your UV map comes from the base/simplest level, no matter how many times you’ve subdivided it for sculpting. I could be wrong – but it appears to be the case when I look at for example the UV map of the multires pancake from the pancake hobo course.
I don’t think you really need to bake a normal map unless you plan to export the model to a game engine for example.