The team does not need many star players in the squad for a good performance. We have seen proof of this several times. The Chelsea team won the Champions League title a few years ago. They did not have many star players in their squad. Leverkusen are still unbeaten in the Bundesliga and Europa League this season. This team also has no star players in its squad.
PSG had many star players in their squad, but their coach was not good. There was no friendly relationship between the players in the squad. PSG team cannot do well in Champions League due to lack of friendly relationship between players and lack of understanding between players. But now PSG has an experienced coach like Luis Enrique. Now, if PSG's squad was as strong in attack as before, PSG would have been able to dominate the Champions League.
Of course you need star players and I have no idea what your definition of a star player is. If the only guys who can be called stars are Messi, Ronaldo and Mbappe then you are right because they can't be everywhere and two of them play abroad. But of course do these teams need stars to win the Champions League. Some of them might not be as well known as others, but all of them are stars in some capacity.
You are applying some weird logic to be honest. Since PSG never won the Champions League although they had Mbappe, no team that has Mbappe will ever win the Champions League. That is how you construct your arguments. Think about it.