The major challenge of Barcelona is that they don't like to spend huge amount of money to buy potential players that will add value to the team like other teams. I can still remember huge amount of money Real Madrid coach spend to signed one striker from PSG that is making the team to remain stronger till now, because Real Madrid performed well in many tournaments to ended up among the top teams in the tournaments, and they have qualify for semi final in the FIFA club world cup this season.
Where is the money for Barcelona to spend on buying potential players as you said, it's not as if they have the money and refused to buy quality players to the squad so in reality, they do not have the money. It has been recorded that since 2017-2018 season, Barcelona have been in financial crisis and the situation worsened after the COVID-19 pandemic in 2020, and ever since then they have been unable to recover from that financial mayhem which resulted from gross mismanagement of funds. It is needless to talk about Real Madrid's expenses on world class players because they have been in the limelight of football for over a decade now, winning both the La Liga titles and European titles namely the Champions League which they made huge amount of money. Do you know that excessive expenses on signings and salaries of players was also a contributing factor that led to Barcelona's current financial state? Barcelona is still owing debt and even owing players salaries so there is absolutely no money to spend on new signings which means they will need to manage the current squad till they reach a certain level of financial balance.