Do you want him to reduce his salary because of the condition of the team? Not all players can do that. They will have gotten a good pay like this elsewhere but decided to stay here and play for them despite their financial condition which can affect their own performance also because if there are no good players to play alongside them, they’ll all fail as a team and won’t make them happy to do better next time and be looking for means to leave the club. Barcelona needs to fix their financial crisis to be in a better position for any competition they’re participating in, the claim shouldn’t be put on any player collecting big pay or not.
So why is Frankie de Jong still not for sale? If you really want to fix the financial crisis, of course something has to be sacrificed. I think it is realistic to sell de Jong, who with his sale can provide some relief to improve the team by utilizing the sales proceeds to buy players who are desired but whose prices are still affordable. They want Nico Williams now because many rumors say that if they want to bring in Williams, Barcelona will receive FFP sanctions. Lewandowski is old, ideal to be replaced by a younger generation and suitable to be paired with Yamal. This is a consequence that Barcelona must take in order to avoid sanctions and increasingly messy finances. Totally improving finances is not a good solution, and Barcelona will not be able to do it other than improving little by little.
All of what you have recommended as a possible alternative solution that Barcelona can undertake to ameliorate their financial problem do sound good on paper but not that simple to apply it practical, as am sure the experts in the club would have swing into making this happen if it was going to work or give the best possible result to the club. Because bringing in Nico Williams with the aim of pairing with Lamine Yamal doesn't make the Barcelona team invisible on the pitch for next season. They shouldn't due to one young boy that looks promising to the club sell out their experience players.