So in my personal opinion, if Manchester United wants to rise again quickly, I think they should replace their entire management team and replace them with a better management team.
I have actually discussed this before and spoken about it. The majority of players who left Man United were able to perform well with their new clubs. Analysis has proven this to be true. So the players are the least of the problems. I think Man United needs to make major internal improvements. Perhaps this is down to management or the coaching team. I understand that players' professionalism is shaped by the team atmosphere. If the team atmosphere is bad and management is poor, then they will not perform to their full potential in games. Amorim has a tough task ahead of him; it's been a year, and this is his second year. If he fails again to improve Manchester United's performance, I feel the supporters will grow increasingly impatient, and he might be fired.
Looking at Manchester United's start to the season, I don't think it'll be long before Amorim is sacked, even though they've only played two games this season. However, considering Manchester United's performance hasn't improved compared to last season, I don't think there's much hope for them this season. They won't be much better than last season.
I also believe that Manchester United's players aren't to blame for their poor performance. In fact, in recent seasons, the Manchester United squad has been full of quality players, but they haven't been able to lift the team. The problem lies within, unseen. If that isn't addressed, Manchester United will never recover, even if they spend more money.