Most of these stars you are talking about are young and they don't have enough experience or some of these younger talents are in the teams they can't be in the Champions League just like Harry Kane who playing for Tottenham for years and he has been a good player but his team can't achieve anything yet.
Victor Osimhen is another example who plays for Napoli and he can't have too much hope for winning the title with his team.
For Osimhen and Napoli it was a great season and they had a very good chance of getting better results in the Champions League. Whether Osimhen can still reach the same heights with Napoli, I'm not sure, but he has a good striker and if he can continue to show such a good game, then he will have a good chance of moving to a top club with which he can do it. So far, it's clear that Osimhen would like to stay at Napoli and win trophies with this team, but it's not as easy as he thinks.