Manchester united is in its transforming stage, it will take time before they will bounce back to winning ways because there's a whole of things to set by the coach and the players will have to abide by strict rules set. Erik Ten Hag have his own ego to float, we know him to be one of the tough coaches that have managed Manchester United and he's not going to relent when it comes to his duties as headcoach. He discipline his players accordingly and he share the exact same respect and commitment to all of them despite the high status of some players.
It's true as you said, Man United really has to be patient and it will take time for them to return to being the team most feared by opponents in the EPL under Erik Hag's tag. But sometimes Erik Tag Hag's discipline is also too much in my opinion, just look at the example when Erik Tag Hag called out Sancho for not training well then sent him away but continued to play Rashford regardless of how bad he was hmm so I guess Rashford trains very well but can't do it in the game the truth, and what's strange is that when Rashford doesn't perform well but Erik Tag always plays him.
In essence, in my opinion, Erik Tag Hag must be stricter with players who cannot show their best game by substituting these players, not just disciplining players who are disobedient.