United's financial situation is a complete mess. All these years of buying recklessly and getting nothing in return (outgoings) and their lack of UCL football this season (and probably the next ones, too) have put them in FFP & PSR territory and they are now forced to sell in order to buy any more players. If Amorim wants new players, he must sell first, there is no way about it anymore. Mainoo represents pure profit, but he is no way an 80-100M player as those deluded muppets at RedCafe think. United are desperate and clubs know this and their squad options are limited in terms of what players represent any value in the market in terms of FFP and PSR. Because if they want to sell Hojlund for less than 74M two years after they bought him for that amount, they are in an even bigger trouble as the deal would be registered as a loss. Same goes for Mount, or Zirkzee or all of the other bang average players they bought in the last couple of years. They cannot sell them at a loss for the moment. They will probably try to sell Mainoo and Garnacho and get rid of the big wages like Rashford, Casemiro, Eriksen to free up some space.
At the moment I believe United try to make Mainoo look like a w**ker in the media to please their fans when they will eventually sell him, telling them he did not want to play for them anymore and wanted a new fat contract. Truth is they are in such a big mess, they are forced to sell him if they are to even think of new signings.