The major issues for flick would be the fact that Barcelona themselves are almost entirely broke and for a club like Barcelona that wants to return to their former glory they would definitely need to bring in some players and that would require funds which at the moment seems to be some of their issues but even at that I still expect them to be different atleast they have some good players, it just all boils down to the fact that a good coach with good mentality needs to handle the club.
Even though he knows that Barcelona has financial problems and the club is almost bankrupt, this coach still accepts an offer from Barcelona to coach this club which is not in a good condition. Hopefully it can be as expected by the fans. This coach can restore Barcelona's confidence. Let's see how he manages Barcelona next season. He has experience coaching big clubs. Hopefully this experience will make Barcelona even better. Even though Barcelona can't buy players, at least Barcelona still has quite good players if they are trained well.
In the midst of Barcelona's conditions like this, it is indeed a challenge for the coach to improve the club's performance, but the most important thing is that the coach is able to handle it and doesn't mind it even if his salary at Barcelona is not that big even though he coaches a big club. I heard that Hansi Flick is very passionate about coaching. There was even news about his new club that he entered early to work at this club, which means he has strong enthusiasm and ambition. I think he is starting to think about strategy and wants to try a coaching system that is suitable for his players so that next season they are ready to compete fiercely with Real Madrid's again arch rival.