The problem between Sancho and Manchester United is not as simple as we see, Sancho loan period at Dortmund will of course end soon and reportedly currently Manchester United is starting to have talks with sancho about his future, whether he wants to leave or stay at Manchester United next season, while what is more complicated is of course Sancho request to Manchester United who indeed asks to choose Sancho or Ten Hag, It seems that indeed the dispute between Sancho and Ten Hag is the main point of the problem and of course it will not be easy to resolve considering that both parties have very big egos so far.
Sancho has performed quite well with Dortmund at the moment and of course makes Manchester United again interested in returning him to Old Trafford, but reportedly Sancho only wants to return to play for Manchester United if they sack Ten Hag as coach, so indeed this makes Manchester United quite a dilemma to choose Sancho or Ten Hag, currently Sancho price has of course risen dramatically after his brilliant performance with Dortmund at the moment.
the best solution is for Man United management to give up one of the two parties and if that choice was made to me, I would choose to keep Ten Hag.
I don't think Sancho is bad, but if a player wants to join a team but has tough conditions, in the end the player will remain selfish in the future whereas Man United doesn't need a selfish player like that even though he is an adult who must have the best principles or choose to leave Man United if you really don't want to see Ten Hag again.
giving the condition that he wants to return to Man United as long as Ten Hag is fired is not the best solution, whereas Ten Hag once helped Man United finish in the best position and now has to comply with Sancho unreasonable demands.
even though he has good talent and can develop at Dortmund, if he joins Man United again when there are problems, he will definitely continue like that as if the team is spoiling him and now Man United must be wiser in taking steps rather than having bad times again.
chose to keep Ten Hag and sell Sancho to buy another player who could value the team more.