Leonardo Jardim

The former Monaco manager has created quite a reputation for himself after leading Monaco to the French league title, beating the free-spending PSG in the process. Ever since the principality side changed their clubs structure from spending big to sign the best, to invest in the best young players, the club has made a lot of progress and a lot of it is down to Jardim.
Under his stewardship the likes of Martial, Mbappe, Bernado Silva, Thomas Lemar, Benjamin Mendy, Tiemoue Bakayoko, Kieta Blade among others have. In all, Jardim has amassed the club a total over €400 million in player sales. The main learning from this is that every season, his team got torn apart by bigger clubs, instead of whining about it, he unearthed new talent and gave them the opportunity to show the world what they've got.
Jardim would be great in bringing through players from the youth system. Baring Rashford and Lingard not a lot of academy players have been able to make a name for themselves at the club. The fans would love nothing more than seeing more of their own players down the red of United and walk onto the green of Old Trafford.
Jardim over the period of just two seasons took Monaco from a midtable team to a league winning side. In his first season, he looked to create a strong defence and in the next built a potent attack with the strong defence already there behind them. This blueprint would work perfectly for United.
Manchester United already have a great attack on paper. The midfield too is comparable to other top 6 sides, the defence is the only issue. A couple of signings and Jardim's philosophy in place, Manchester United would be rubbing shoulders with the best in Europe again.