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.
Which is how Madrid is playing, and people believe they aren't trying, making it harder for them to score goals in the league. I believe Ancelotti will return to fitness and score goals, challenging other teams in other competitions. Barcelona is doing well this season, and no one believes they will be stronger this season because they do not have enough money to buy key players for the team, but even with the small players they have, they are dominating the league and believe they can be champions this season
Let's see how the competition ends, all Madrid fans anticipate Madrid to do well because they have Mbappe, but he isn't in great shape and can't score goals like he did at PSG. Mbappe will need time to fully understand Madrid, as the competition is more interesting and has more challenging clubs. I don't blame him if he isn't performing well, as I believe he will gradually improve his fitness. Many of his goals in the competition are penalties, Ancelotti need to do something different so that Mbappe can get more chances to score goals.