But sorry, Real Madrid has a good plan in regenerating the squad, in fact Real Madrid also still has many young players with great potential in the squad. Not only that, even some senior players are still in the Real Madrid squad and thus, even if Real Madrid the player you mentioned is injured but I still think Real Madrid is still fine. Last season, Belingham made a huge contribution to Real Madrid's success in winning the trophy but this season, after suffering an injury, it seems that Bellingham has also decreased. So, in the not-so-good results for Real Madrid so far, I don't think it's because of Mbappe but yes, because it seems like the other key players that Real Madrid have also experienced a decline in performance this season.
Bellingham was the top scorer of Madrid's squad last season. Bellingham is not in good form this season. He has only scored 4 goals and 3 assists in 11 matches. In addition, Vini is now facing injury again. Mbappe is not getting the expected good performance. Even Madrid has lost points in several matches due to Mbappe's bad performance. It is not possible to say for sure whether Madrid will be able to play well in the upcoming matches of the Champions League.
Madrid will play against Atalanta in the next match of the Champions League. Atalanta team is very strong this season. So if Madrid players do not perform well, Madrid has no chance of getting points against Atalanta. I consider Atalanta team as favorite in this match.