Are you sure that you know when Amorim took over from Ten Hag. It was close go the middle of th3 season and that means he hasn't spent up to one season. You should see the weak players that Ten Hag bought which led to his sack. How do you expect a new coach to use such players to achieve a better result. Amorim only focused more on Europa League last season and he almost won the trophy but the same weak players messed it up. I can boldly tell you that currently, United have a game pattern unlike, when Ten Hag was in charge.
The difference is definitely in the change of coach with Ten Hag being replaced by Amorin of course it is difficult to improve the team because it needs to replace players because it is something that needs to be considered in every team. However, there must be the most prominent answer to the need to bring in quality players and that is a simple answer to the existing shortcomings, even though it has to spend a lot of money but behind it there will be an opportunity to rise again.
Many may say that Manchester United have performed poorly since Ten Hag took over, but even after Amorim took over Manchester United, he has not been able to change much in Manchester United's performance. To those who say that, I say that Amorim took over a messy team and since he took over the team, he has not been able to bring any significant player to the club as he wants. First, Manchester United should let him bring some players to their club as he wants and see him for a season. If he can change the team's situation in this one season, then plan for the long term with him, but if the club's performance remains the same despite changing players, then Manchester United will have to assume again that they need to change their manager.