I remember there were several players who deliberately did not play at their best because they didn't like the coach. They played so badly that the coach was sacked for poor performance, it worked and I really wonder if that scenario was thought of by a handful of Manchester United players? If that exists, then I'm sure that in the end Ten Hag will be fired even though he managed to lead Manchester United to qualify for the current Champions League.
The responsibilities of a coach of a team is huge. The manager would be held responsible for any poor performance from his players as he is expected to be able to do whatever he can to always bring out the best in the abilities of his players.
A handful of players who deliberately choose not play at their best cause they have some grievances and don’t like the coach won’t be good for the teams overall performance and the coach is the one would bear the majority of the blame for the poor performance of the team.
I’m also quite certain that Ten Hag would be replaced later on if there isn’t any significant improvement in the performance of the team.