Selling Dybala is going to make our team worse. This approach of selling our best players is not sustainable in the long term, and we definitely don't need to waste money on a goalkeeper when we already have the Pole. Dea Gea is not for sale, as Man Utd are not a selling club, and if he were to leave, he'd go to Real Madrid. Donarruma isn't worth 100 or even 80 million at this point. I wouldn't sell Dybala, not even for 200 million, because I don't trust the management to replace him adequately, and there isn't anyone out there who's available and affordable.
Now, if you say selling Higuain for 60-70 million and a couple of fringe players to improve our squad, I might actually agree with you.