Manchester United did not want to sell him too far below a certain price and Real Betis could not afford to buy Antony, that is why he returned to Manchester United. He started enjoying his game again and played with a smile but it did not work out even though Real Betis wanted him to stay.
As for Sancho, yes he is earning around £300,000 per week therefore they want to get him off their books but he has no offers. Only Juventus are contemplating making an offer. If they sell or loan out Antony, Malacia, Garnacho and Sancho they will save around £700,000 per week (now that Rashford has moved that saves another £325,000) therefore £1 million a week.
Sancho disappointed during his loan at Chelsea, they never really wanted him because of his inconsistency therefore sent him back. I think he already peaked when he was 21 years old at Borussia Dortmund. That was the age Manchester United paid £73 million to buy him. His contract expires at the end of next season therefore rather than let him leave for free they will try to recoup some money for him by selling him.
If Sancho refuses to leave he will earn £300,000 per week unil July 2026 and then become a free agent but with a reputation for being difficult, which team will bother taking a risk on buying him if he becomes a free agent?
Sancho's weekly wages are also reportedly around 300k/week; Chelsea offered 160k/week, which he declined, so he's accepting a massive paycut to persuade Juventus to move, but the deal is still pending. He must be regretting not accepting the Chelsea offer when he had the opportunity; now no one wants to sign, and there are only a few days left.
I'm surprised Real Betis didn't sign Antony after his fantasy season with them; perhaps they rewatched clips from the Conference league, saw how he ghosted, and chose not to sign him.