He is a striker and does not have good skills to play as an attacking midfielder or even as a forward. He is not like Messi or Dybala who feels more comfortable by playing as a forward, play maker or attacking midfielder.
I don't know about his skills, but it should be not comfortable to play in that position because it is not his ideal position. Julián Álvarez can play as a second striker, but I doubt he will play with his best as an attacking midfielder. Sure, he isn't Messi who can play in many position. It is because Julián Álvarez always played as a striker so far.
I agree with you that Guardiola knows about that and he also knows that Julian has yet developed his skills for an attacking midfielder. Maybe he will try to test Julian with different positions than a striker as it is his style. He also requires his players to be able to play at different positions as it gives him and the club more flexibility in tactics.
Yep. If Guardiola wants to optimize the potential skills of Julián Álvarez, he must put him on the right position. Force Julián Álvarez to play as an attacking midfielder may reduce his potential as a productive striker. We know that Julián Álvarez often makes goals, he must have the desire to score goals as many as possible. He isn't a player who prefers to provide assist for other players.