It is the job of management to solve this problem, and actually this has nothing to do with their new coach, because management is the source of this problem, so they must be responsible for completing what they have done.
Regarding concerns in the Barcelona camp, this is something that is very natural, because after all, financial conditions are something that will greatly influence their performance. In selecting players, they also have to adjust to the money they have.
It is difficult for any coach to handle Barcelona during these difficult times, because they cannot freely do what they want. And even if they need something, it will be very difficult for management to grant it. Indirectly, this is a pressure for coaches, where they have to play optimally while they do not get full support to be able to have the squad they want.
So far, everything is happening the other way around, despite the fact that Barcelona have had financial problems for several years, this does not prevent them from having the best players. Even in this situation, they were able to maintain the squad, and attract players like Gundogan and Lewandowski. There are problems, of course, but this is not an obstacle to acquiring new players, or at least I do not see Barcelona to withhold the salaries of players, which means that they are coping with this problem for now.
Gundogan and Lewandowski are not young players anymore and they are no longer at their top form so I don't think that is a reference.
A team as big as Barcelona should be able to bring in several talented players and compete for titles in La Liga and on the European stage, but in fact right now they can't do that because of the financial problems they are experiencing so it cannot be denied that currently Barcelona is in a slump and that because of their financial problems.