A club that won titles in several competitions such as Paris Saint-Germain, must have a very strong cooperation between players.
When a club has a selfish player, it is impossible for the club to get the title because of the chances of victory in each match greater if done together without relying on just 1 player.
So I agree with your opinion that Kylian Mbappe still has a selfish nature, it is impossible for Real Madrid to win the Champions League this season.
Mbappe cannot do it alone and sometimes the selfishness of some players has an impact on the club's journey in competing for the title. Real Madrid not only talks about Mbappe because they have a number of players who have the best quality even though this season could fail to win the Champions League. I don't think the problem lies in Mbappe who some people say he is selfish because if he is noticed he is different when he is still a PSG player. At Real Madrid the pattern is different because this team is formed on the trust and mentality of champions who are far greater so that any efforts that are done individually often do not go according to the selfishness of the players themselves.