I do not trust that management, because even if you give them a billion dollars, it doesn't look like they will be debt free right away, they will first look at players to buy. They have not made the team any better by firing Xavi neither, he was the one that gave Yamal time when he is only 16 years old and this kid is now playing at euros for Spain. The reality is that Barcelona is mismanaged and there is no getting better unless they change the president and his squad.
I doubt that Hansi Flick will sell any of the young players that Barcelona has, besides that Lamine Yamal is also player who could be very useful for Barcelona in the future, maybe he will make lot of money but that won't help anything.
Now Lamine Yamal also has very large offer, namely around 250 million Euros from PSG and this amount is quite significant increase because we all know that PSG first offer to get him from Barcelona was 200 million Euros.
Just imagine if he is able to play very well for Barcelona and manages to make big contribution to Barcelona development in the future then Lamine Yamal price will definitely be higher.
But who knows what will happen in the future because the transfer window is still quite long and of course anything could change if certain conditions occur that require Barcelona to release their young players.