Sancho is back at the right club, it would be good if he left Manchester United. Even though he played without Sancho, Erik Ten Hag still gave bad results for the team. Dortmund feels they can still utilize Sancho' abilities as before. So I wouldn't question that decision too much. The worse Manchester United's performance, the more it strengthens Sancho argument that Erik Ten Hag is incompetent to handle a club as big as Manchester United.
I agree with you on this but Erik doesn't see it that way especially as of recent he enjoys using the same tactics to expect a different result.
There are rumors that the Red Devils will be active in the transfer market and are already eyeing several players they want to buy to cover the midfield, I might add it would be better to buy another striker, but the biggest difficulty is that Ten Hag always fails to choose players.
For me, it's really not necessary to get new players when you can't fully utilize the potential of the ones you have. He can't manage this ones he has so what's the assurance that he'd be able to do well if they get more players? It will be like wasting funds. Instead of buying more, he should sell some of the wingers and get new and reliable ones rather than adding to the ones that are there already to avoid unnecessary flooding of players in the club.
Let's use Chelsea as an instance, they have a lot of players to the point that the coach becomes confused as to who he'd start and who he'd reserve which makes him end up making wrong decisions so if Man UTD decide to get more players instead of selling some, the problem will become worse for Erik ten Hag.