Manchester United hasn't moved quickly in acquiring new players at the moment, compared to other Premier League teams like Liverpool and Arsenal. In fact, Manchester United were already behind last season, so they need to work hard to secure the players they're targeting and want for next season. Being slumped under a different manager the following season is incredibly painful for Manchester United and its fans. So, raising their offer for one of these players also demonstrates Manchester United's seriousness in acquiring a great player like Mbuemo.
Manchester United has already faced immense losses due to buying players without checking their capabilities. Even though they spend a lot of money to buy players, they do not get good performance from them. Even now Manchester united management is not able to sell players. As far as I know, most of Manchester united players' wages are high. So even if players are kept on the bench all year, Manchester united will suffer financially.
Manchester united should not be in too much of a hurry now. They are facing big problems. They must understand that it is not possible to improve quickly from this problem. If they want to improve quickly , there is a big possibility of facing huge problems. So they should sell players gradually, and find suitable players for the squad.