Yes there is no problem between Kylian Mbappe and Vinicius Jr but mentally i will say that Vinicius Jr felt intimidated when Kylian Mbappe stepped into the squad because initially Vinicius Jr was always the player to look out for but when Mbappe came in, the attention shifted from Vinicius Jr to Kylian Mbappe. However, Real Madrid is very much interested in both players, i don't think they have any plan of selling either of them in the short run so what Xabi Alonso need to do is to see how he can be able to convince both players on the need for them to work together towards the growth of the team and disregard their individual sentiments against each other. Kylian Mbappe is good, same as Vinicius Jr so they should be happy that they are playing in one of the best teams in Europe and they are earning huge, it will be better they stop the competition against each other and understand that the only competition is to beat their opponents and emerge victorious in matches then win trophies for the club.