What Erik ten Hag did was indeed quite appropriate for player discipline, but we also have to see that while Erik ten Hag was coaching Manchester United and at Ajax previously he had a lot of problems as a coach with players, not just with Jadon Sancho, I don't mean to defend Sancho, but I think Tenh Hag also has to lower his ego and prioritize the development of the team he handles.
I think Erik Ten Hag doesn't need to lower his ego. Because ego is necessary for a coach to manage his players. Just think about talented coaches like Sir Alex Ferguson, Mourinho, Antonio Conte, or Jurgen Klopp... what were their egos like? I believe what Ten Hag needs right now is to adjust his ego and personality to be more suitable, so that other players on the team don't lose confidence and believe that he's not favoring anyone on the team. With that, Ten Hag can slowly revive Manchester United.
It is true that all coaches have a tough character or what we often call discipline, circumstances demand this in order to maintain the club performance to remain stable. It's true that Ten Hag needs to make a slight update to his approach with players, without giving them special privileges so as not to cause division in the dressing room. I think things will improve soon if all the injured players are available again, and Ten Hag has several rotation options if there is a decline in performance in the starting XI.
A player self-confidence really depends on the results of previous matches, and their role in contributing to the team during the match. In an unstable situation like the current one, Ten Hag efforts to bring his squad will continue to be challenged. It must be admitted that his second season at Old Trafford was a little more difficult, a series of player injuries, slow adaptation of new players and off-field player scandals made the current situation complex.