I am of the opinion that art is inherently subjective and there is no "best" of any art form. It isn't like the fastest 100m runner where there is one clear answer. To me, the best art is what you like the best. Having said that, to me, The Prince of Egypt is the best animated musical.
As was discussed in the other thread your preference for The Prince of Egypt isn’t debatable as that is inherent in your own pov. As for “best” in this case there are measurable standards such as box office performance, the rotten tomatoes score and other measure of successes. Critically can look at quality of animation, complexity of song structure, along with plot. I think in nearly all of those categories Prince of Egypt falls behind other animated features such as Beauty and the Beast, or Fantasia.