This problem is not new to them. Although I can't speak in depth about Bellingham, the accusations against Kylian Mbappe and Vinicius Junior are not wrong. Mbappe's former PSG team has seen some conflict with Messi and Neymar over this. Vinicius Junior's selfishness is even more evident in the Brazilian national team. The only problem with Real Madrid's attack is selfishness. Even though they have the best attack line in the world, they keep a clean sheet in some matches, mainly because of this selfishness. I think Real Madrid should learn how to perform as a team from teams like Barcelona and PSG.
To be honest the behavior of the players who build such distorted relationships is truly reprehensible because it is true that they should only have the support of the new coach. It is now blindingly obvious that Mbappe a former player for Paris Saint-Germain Football Club was not able to bond well with that team. It may not be correct that Vinicius Junior has such a perverted talent hidden within him, you mentioned that his selfishness is evident even in the Brazil national team.
At the moment I think they lack groupism and if there were cooperative activities among them and if there were no disagreements then this team would definitely have been explosive with PSG in the Club World Cup.
PSG has tried everything to keep Mbappe and even after Luis Enrique took charge, they have tried how to keep Mbappe because Mbappe was the most valuable and important striker of PSG at that time. But when PSG could not keep Mbappe, Luis Enrique was forced to plan with their team's internal players and organize the team accordingly. The club management may not have expected so much from this starless team at the beginning, but Luis Enrique has changed the team's strategy so perfectly and is applying those strategies in every match, which has resulted in a big change in PSG's internal structure in a short time. The team is now as balanced as it is, even if the PSG management does not recruit any new players for their club for the next season, the team's performance will continue like this.