The shapeshifter and the villain are both trying to stop or even kill the hero and prevent him from carrying out his destiny. Which do you think is more harmful to the hero’s journey? Why?

Shapeshifter causes more harm to the hero's journey than Villain in fulfilling heros' destiny.

Explanation:

Because, Considering a villain is a person or an image which is stable. Whereas in the case of Shapeshifters, they can take up any of the shape. Sometimes a person or an object which would be impossible to detect and destroy. For example, let us consider "Captain Marvel" movie where Vers had to deal with Skrulls who are basically shape shifters. The writers made Skrulls to be in the good side. Let's take a moment to think how hard for Danvers to deal with shapeshifting villains. Hence the rather than Villain, the shapeshifters cause more harm in fulfilling hero's destiny.

I think the shapeshifter would be more harmful to a hero's journey because it’s not always a creature that turns to an animal, but it could be a friend of the hero who betrays them. I think having someone close to you turn on you and leave you, would be more hurtful than a villain who you know has it out for you, and the feeling is mutual. It would be much more difficult to have to fight someone you cared about than someone you hated.

they insisted that there was not enough time to learn everything.  

explanation:

if they were going to steal the answers that is simply because they insisted that there was not enough time to learn everything.