It is not certain that Mbappe will shine in Real Madrid. I wish him all the best but we have seen players with great potential flopping immediately after they move to a new league. It happened to Andriy Shevchenko, Fernando Torres, and many others. He is still getting used to the Spanish League and also has not had a bad time, having scored three times in the La Liga. The season will continue after the international break and we will also enter the Champions League season. Many pundits are concerned about the poor attacking force of Real Madrid, but they will keep getting better, hopefully.
Mbape has just proved that Laliga is more competitive and highly hard than Ligue1 because the expectation that Real Madrid fans are expecting from him looks more like they want him to be like the next Ronaldo and the way we have young faces in among the team, it will be difficult. Look at how good Bellingham has been since he came, Vinicious is there as well and Rodrigo is looking for more more opportunities to shine too among this pairs, it will be a problem for Mbape to fit in here.
Another challenge that I point is that each of these players are also greedy. During Ronaldo time, he is good at making his own goal but most of the time he got supports from wingers but the current wingers in Real Madrid want to make goals too even the midfielders like Bellingham are doing the work or striker because they all want to make a personal achievements so they can get a high rating, these factors will hinder Mbape from getting more goals as many people are expecting from him.