Look at the midfilders United have in comparison to other big teams. It's a 32 year old Casemiro along with nobody that stands out. His new midfielder Amrabat hadn't even been playing as a CM since coming into the side which is absolutely ridiculous.
This is the main problem.
City without Rodri is at United level in numbers albeit not in performance.
Spurs have lost Kane. But now they look better with
Maddison & Bissouma.
Liverpool striker is Gakpo. Gakpo. They revamped their midfield they look better. Liverpool of before had Firmino as it's striker.
Arsenal changed their midfield this season , you can see how it changed their game a level below.
Madrid of 3* UCL wins had Modric, Kross, Case.
Barca of Pep had Xavi, Iniesta Busquest.
Chelsea of Mourinho had Lampard Essien & Makelele
Even Leicester winning title midfield had Kante,
Albrighton players who could run till morning.
As you can see, you need most importantly 3 absolute good midfielders to have any hope of winning anything big.
City have won the league without a striker.
Arsenal mounted a challenge with Nketiah.
Liverpool won 27 games in 29 games, to win the league with Firmino scoring only 9 goals that season.
As you can see, teams have won the league with very poor strikers but never has a team won the league with a poor midfield.
Yet our midfield is the most unbalanced part of our team.
Until ETH revamps our midfield, we will never win anything.