Yes you are right, when the news of the signing of Mbappe to Real Madrid was heard everyone believed that Real Madrid team was going to be undefeated this season because of their performance last season and the players they have in the team and everyone was expecting them to be strong this season but they are yet to master with their current formation that's why the team is struggling in so far this season I don't think it is injury issues.
The great expectations of most people make the situation that Madrid currently has look bad because it does not match their expectations even though when we look at what happened it seems normal because it is not only Madrid who did this even Barcelona also experienced the same thing just because in the end there are players who are very good like Mbappe and Vini in attack as if Madrid is very bad now.
The fact is that Madrid is not that bad even if you look at what is happening right now in La Liga, Madrid and Atletico are the ones who still haven't lost even once in 9 weeks of the current season so we overestimate just because the draw is considered a setback for Madrid when their performance is not that bad.