The truth is that Mason mount don't have any choice but to give his best performance for Manchester United, with the number given to him other players, fans are looking up to him, I think this will motivate him to do better . To me I feel Mason Mount will do better under Manchester United, he is an experienced player with a good performance, I don't think Manchester United will be too hard for him to perform well in the new season. For Manchester United to able to bring Mason Mount into the squad it is a good achievement for the season.
Mount is a player that would have an instant impact if he plays his best, dude has been playing well for a few years now and he could definitely provide a lot to the team right away.
However, the job falls on the coach a bit as well, we all know how Mount plays, if he makes him play the way he likes to play then he would definitely provide some good impact, or at least he would be asked to play the way he has been playing, but if the coach asks him to play differently then we are going to see him do a bit differently and that's going to hurt his chances to play well, ETH definitely makes players play better, we have seen that so far and I have complete trust in him that he will be capable of asking Mount to play better and get the best out of him as well.