Manchester United has enough players in the team but those players are currently performing very poorly. If a new coach joins the team and implements new strategies and tactics, hopefully the team will return to its previous performance.
I think only a few players, we can't rule out players who have work hard to keep Manchester United at the top of the standings like Marcus Rashford for example, and there are a few more players.
If look at Manchester United's overall gains in the EPL, they are currently still pretty good and we can see Man Utd are still dominate the third and fourth positions in the EPL.
That's why a team must have a good squad depth, so when their main players can't be used they still have substitute players who can do well. That's what Manchester United now doesn't have, so they struggle when the main players have to be absent for several reasons, one of which is injury. This is what the coaching staff has to look at, where they really have to have a reliable replacement player. This is something that really needs to be considered, considering that their playing schedule is also very busy when they participate in several competitions and one season.