I would put all the blame on Ten Hag because he is the only coach that has used a huge amount of money to buy players above their value which is affecting the club performance and financial state. All most all the players he bought are all average players who cannot withstand the pressure in the EPL competition. United bought the wrong players and expected a magic or what.
I won’t blame Ten hag entirely for Manchester United poor performance, Ten hag spent huge amount of money signing players, he signed players which he think will improve Manchester United performance, but he ended up signing the wrong set of players, most of the players he signed were performing well in their previous clubs that they played for, but immediately they joined Manchester United, things changed, they started performing poorly, and Manchester United performance has been getting worst.
What Manchester United should do now is to sell some players thats not really useful to them, and then sign new players, if Manchester United performance doesn’t improve after signing new players, then I will say Manchester United problem is not from players.
Ten hag should be blamed for bringing players that are not useful to the team with so much amount of money, he spent huge amount of money to buy players but he couldn't manage the players properly he was just having issues with most of them that he forgot to focus on how to get the players back to their feet when they were losing form. Ten hag made a big mistake when his team was not performing well, instead of changing the pattern of the team he decided to start playing some of the players off their position and it made most of them not to perform well when ever they play.
Amorim needs to take the opportunity to sell the players that are not being helpful to the team and the players that has not been used it he can replace them with a good players Manchester United will experience improvement in the team.