Hansi Flick may bring many changes to Barcelona next season, but this will not mean that Barcelona will be able to easily compete with Madrid, barcelona deteriorating financial condition is of course the reason that Hansi Flick will not be able to optimize his ambitions with Barcelona, so I think next season we won't see many differences in the competition between Barcelona and Madrid compared to last season, so it is very likely that Barcelona will only try to compete as title contenders but not as title winners in end season.
I also still think like that where Barcelona can still be a team that challenges for the La Liga title, but I'm not sure Barcelona can immediately return to win the La Liga title next season with its new coach. Because Real Madrid is still trained by a coach who is quite skilled and has very, very talented players in the squad, it will certainly make more of a difference to the players in the Barcelona squad itself. Although Hansi Flick himself is determined to continue trying to turn Barcelona into a better team than last season next season.
Considering the situations at Barcelona, I don't the club's management will be expecting their new manager Hansi Flick to have an instant impact on the team. Barcelona haven't been active in the transfer market in recent transfer windows and even had to rely on some players that were brought on loan from other to clubs to remain competitive but after the end of their loan deal with the Spanish club, Barcelona allowed them leave the club instead of permanenting their deals so they will have to rebuild the team to become very strong again before they can talk of winning trophies.
Another reason why I don't expect Hansi Flick to start winning trophies in his first season at the club is because Barcelona's biggest rivals in the country Real Madrid now have a squad that's full of the best players in the world at the moment and considering Real Madrid's quality and depth, I don't expect a club like Barcelona to win any domestic trophy ahead of them. Hansi Flick is a great manager with incredible records but I think his first season at Barcelona will mostly be centered on rebuilding Catalonian club