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.
Thanks to this nations league break, he had some time to adjust with the team and that way he could probably call up some players for training and such, and keep trying to watch more and more games, focusing on every little bit of detail and every single player. It's obvious that they do have a decent core, I mean Onana started terrible last season but not that terrible this season, we all know Bruno is great, he is still great if you ask me while I know he wasn't that good this season.
With all that in mind, I like De Ligt, Mainoo, Garnacho, Rashford and Hojlund. Not saying they can't be sold or anything but I believe they are good enough to get higher. So what Amorim needs to do is try to figure out how to keep the team going towards better instead of worse. We have seen them not have that much of a big change on the long run and eventually Amorim will take them better step by step and build a better team if you ask me, he just needs some time.