I think they need to sack him,he was given too much time as a coach and didnt do anything and just shows bad rep for the club with all of his decision. After Ronaldo it goes downwards and that is a serious problem for the club. Players dont like him and that can only cause problems,he cannot replace all of the players.
Too much time? 
Man United hired him on July, 2022. His contract will expire on June, 2025. He is just 2 seasons with Man United. How can you think it is too much time? If you know Sir Alex Ferguson, he needs few seasons to succeed with Man United. So, why don't to give him more time to manage Man United?
Anyway, what he did in Man United isn't very bad. He could lead Man United to finish at the top 3 in the last season. I think we must appreciate that achievement, it is something quite well for his first season with Man United. For the current season, I admit it is not very satisfying. Man United is in the 10th place now. But the season isn't over yet, Man United has a chance to return to the UCL zone again.
If Man sack Ten Hag, I'm not sure they can replace him with an appropriate coach. There are no many top coaches for the candidates. Zidane or Conte seems to have small chance to manage Man United.
Brother Man, Zidane is overrated in my own opinion, right now Pochetino is doing better than he is doing. All the media do is praise him with his past success and glory with a club who needs little coaching to win anything.
Antonio Conte barely gives a shit about the development of the club and young, he is all for the give me money to spend on players that are already made. He may likely be successful but that can only happen with clubs that has enough money to spend.
Erik Ten Hag was the best coach with experience working with younger players and talents. Man United just have too many problems to solve.