With Hansi Flick, Barcelona will try to bring in new players, but they also have to keep important names in the team. Flick also needs to know how to keep players who can be important for Barcelona, because it is critical to keep players who play in their own region, such as Yamal, Pedri, Gavi, Ter Stegen, De Jong, in the team. The team may become even weaker because one or more of these players are sent off from the team.
Indeed, Barcelona really needs to bring in new players with the aim of making the atmosphere fresh and improving Barcelona's performance. Even though Barcelona is currently not doing well financially, bringing in new players is something that is needed if Barcelona wants to become champions in Laliga next season. and honestly, I'm curious about Hansi Flick's strategy that will be applied to the Barcelona players.
Yes, Barcelona are certainly have good players and indeed Barcelona needs to retain good players as you mentioned. and indeed, if for example strong players from Barcelona are not retained by Barcelona then Barcelona's performance will definitely decline and Barcelona will find it difficult to potentially become champions in Laliga next season.
However, I have also heard rumors that Barcelona are targeting young players on loan and according to the news I have read, Barcelona want Hull City winger Jaden Philogene and it seems that talks are already underway. and I think this is a good step for Barcelona to improve its performance in the coming season. and also with the young players that Barcelona currently has such as Yamal, Pedri and others, hopefully Barcelona will add new players to Barcelona to make Barcelona even better in the coming season. Yes, I hope Barcelona can retain the young players Barcelona currently has because of course this will have the potential to become a valuable asset for Barcelona in the future if Barcelona's young players continue to improve in performance.