Casemiro is a defensive midfielder, not a playmaker. Just because Ten Hag is bad at using the tools at his disposal does not mean that the tools are bad, but rather that Ten Hag is a fool. In addition, the fouls he commits do not mean that he is to blame for them, for example recently when Onana made a bad pass and Casemiro had to make a foul to save the team from a goal, it was Onana's fault and not Casemiro.
Erik Ten Hag is among the problem of United, making poor decisions that affects the team's performance on the pitch, having issues with players and favoritism is gradually killing the fire in the Red Devils. Carlos Henrique Casimiro happen to be one of the important player for Manchester United and keyman for Erik Ten Hag. The Brazilian is known to be an aggressive defensive midfielder that have made few dangerous tackles that led to issuing him a straight yellow cards and red cards. There's more he would contributes to the team but in his absence, United defendlines seems to be more vulnerable and André Onana keeps conceding goals in every single game fixture.
Manchester United has been having a series of poor matches recently, but the management board still believes in Erik ten Hag, and they have yet to make any moves to replace ten Hag. He still has too many unresolved problems, and I hope Ten Hag will find a solution and get Sancho back on the field. In addition, Ten Hag needs to help Onana quickly regain confidence, balance, and inspiration to play football.
I don't rate Casemiro very highly, and he became sloppy in possession situations. He's been rusty on interceptions, needs better ball handling, and has declined defensively this season. Putting Casemiro on the bench and giving McTominay a chance is a possible solution for Man United in the coming period.