Moreover, Amorim also respects his own team and tries not to betray them to give a place to the previous staff, I'm sure Ruud can understand it, the club must also respect Amorim's decision because if it is forced it will not be good for the club because working together also requires adaptation and chemistry.
Amorim needs time to get the current Manchester United squad to be prepared for the rest of the season. We shouldn't use the impact that Ruud got to expect same thing from Amorim. The players knew that their position weren't guaranteed with Ruud therefore they played very well to try and get more playing time but under the new permanent manager, after some players get it that they're part of the first team, they won't be overplaying again but to reserve their strength for other games therefore we mightn't be getting the same energy we use to get from them and it can affect the teams performance therefore it depends on how the manager handle the situation.
I am sure Ruben Amorim understands what he has to do to start a new season in the Premier League with Man United, therefore he does not want to get involved with Man United's past because he might fix the players who suit his character and he also has his own coaching system, the players must show their best performance so that the coach can rely on them without having to replace some more players. I think Man United still has a good squad if it is honed well like Ruud can do after Ten Hag left the club.