I feel your frustration bro, spending so much to sign a player that ends up as flop and still having issues with his coach is very frustrating. He showed sign of disrespect and it was right for the coach to take the necessary action. It is the right thing for the team and the player to part ways to serve as a reminder for others that want to follow his footsteps.
Erik Ten Hag is very strict when it comes to dealings with his players, he doesn't open any room for tolerating recalcitrant actions portrayed by his players, he ensure to discipline them and also make enquiries to dropped such player and Jadon Sancho happen to be on the lists of players that failed to tender their regard and acknowledge the presence of Erik Ten Hag.
Jadon Sancho was valued to be important for Manchester United following the outstanding performance he exhibited for the club. Perhaps he will pave his way to the exits doors of Old Trafford and it will become an intended bid to become available as free agent.
We all saw what happened with Sancho after he actually left Manchester united, the boy practically excelled and play better with a different coach and he was part of the squad that actually helped Dortmund get to the finals of the champions league finals although they lost to Real Madrid but everyone saw the impact Sancho had with that Dortmund team and I am certain of he was at united he wouldn't have such brilliance cause of the effect of the coach.