I agree with you. Even though Barcelona has a serious financial crisis, if they sell De Jong and recruit another player with the same quality or more then they will still have to pay the same salary as De Jong receives. I heard news or rumors that said De Jong would be sold because the club management planned to recruit Bernardo Silva from City. I think De Jong is a good player but unfortunately he often suffers from injuries so his performance is not optimal. This is similar to Dembele before, where Dembele often suffered injuries at Barcelona but strangely he became a quite strong player at PSG.
De Jong should definitely be kept by Barcelona. I believe he is one of the really skilled midfielders in the world now. He has been a consistent player since he joined Barcelona as well. As long as Barcelona doesn't manage to find a talent similar to him and much cheaper too, it isn't reasonable to sell him.
Bernardo Silva transfer would probably fail. He has renewed his contract until 2026 and he is happy at Manchester City.Barcelona finances have been a meme topic recently.
After they signed Hansi Flick there was a meme created like they couldn't arrange a car for him that he had to go to the team facilities by bus. 
I hope Barcelona solves the existing financial problems to strengthen the squad more. Otherwise it is hard to compete with Real Madrid.
That is impossible to happen because laporta unwilling to sell his players who already valued very high at this moment. Barcelona continues to refuse to sell its players for higher prices and this is the main problem that was making club so struggle with its financial. Its financial can never recover caused by barcelona has a very bad habit to keep any players till they leave as free agent. When Barcelona received a large offer for its young players, the club rejected it, but Laporta attempted to sell its useless players for a high price which didn't even make sense. .
Who the hell is going to buy them? Ansu fati is the best example of this. Barcelona turned down a $100 million offer for him a few years ago, and his price is now worthless.
They never learnt. Mismanagement is also exacerbating the issue at the club. Barcelona may take more than a decade to rebuild its finances without selling off its skills for a large quantity of money.