Although it is not impossible, re-signing Neymar or Messi is not a wise policy. In line with you, an expensive salary will not be commensurate with the contribution he can make to the club because he is no longer young. It's better to take advantage of potential young players from the academy, give them playing minutes and orbit them like Lamine Yamal. Like Ronaldo, there is actually no drama in his move, Ronaldo demands more playing minutes and doesn't like to be left on the bench. Ten Hag does not want to take a big risk by always including him in the XI if there is minimal contribution, considering the age factor and the competitiveness of the EPL.
Regarding Joao Felix and Cancelo, if they can be consistent with their performance, it is very likely that Xavi will try to make them permanent at the end of the season. It could be that by releasing several other players, it will cover the costs of recruiting both or one of them.
Is better for them to sign young players than to sign Neymar or Messi in Barcelona again, because that is not possible because there are already old players they can't confirm like before again, they have already started losing form just leave them they should continue playing in the Saudi league, am very sure even Barcelona needs Messi back, definitely they need to sell many of their players so that they can pay him salary, because it is not small money they will look for before signing him, Joao Felix is a very good player who is giving his all for the club. I believe Xavi will try to make him a permanent member of the club because he is assisting the club very well with cancelo, Barcelona is very strong this season scoring many goals in the league.