Managers are overrated both in success and defeat. United is playing badly and the players are the first to blame.
I disagree, I think managers are crucial to both the success and failure of a team. I play much more rugby than football, and in it you can really tell if you are playing against a team with a good coach or a poor one. All the players in their best positions, and everyone on the pitch knows exactly what the style of play is and how they fit in into it, as well as hoe everyone else fits into it. That's not the job of the playerstage, but of the coach.
United keep changing their formation and their style of play which is seriously harming them, and I'd attribute part of this loss to that. Against Liverpool, they played a 4-5-1/4-2-3-1 with Pogba playing a free role behind the striker, allowed to go back whenever he wished to. Herrera and Fellaini player as holding midfielders, giving much needed protection to the CBs and allowing the wings to play forward more where they like to play, as there was no space at the back open. Against Chelsea, they played a 4-1-4-1 with Herrera as a holding midfielder. This didn't cover enough space at the back as Herrera isn't a Kante like player who can run tirelessly and protect the back four by himself. He's also more of an attacking player than a solitary CDM. This caused the fullbacks to play more central, to cover the space previously protected by the two holding midfielders and the wingers had to go back and protect the wide channels too. Now, the goals were all individual errors, but mou didn't help his players.
Conte on the other hand began with a useless 4 man at the back formation which wasn't working at all, and has now moved 3 at the back. This works because it suits the players in the team, but also the manager is one of the best in the world at using a 3 man defence, and loves it. Their early season struggle and success noe is not wholly down to Conte, but the manager is the instrumental difference. You saw that with Belgium, a fantastic and talented team with no cohesion or structure because their manager was awful.