Lindelof had covid, I don't know about Bailey. Maguire was fine for us in the previous games and I would say also under Carrick. Varane has been training since before Norwich, so I think we're clutching at straws if we're picking that center back pairing as a big issue on hindsight for the manager.
He has rightly looked at the whole team being an issue, and not really formation related. You need to make better decisions and work harder on the press if you're wearing the United shirt. I don't think Sancho or Bruno or Ronaldo were in too foreign a role. Everyone's been begging to see Greenwood centrally and he operated in the very front, or in the 10 of the central 2 - but was pretty atrocious. So was Rashford.
I don't think 4222 is our system for the long term and I don't think Rangnick thinks this either. But if the players actually pull their fingers out then it would likely protect our defence most. It makes sense for him to try and prioritize this after walking in from Ole's thrashings.
If you ask me the biggest culprits are the ones who we are not discussing. The full backs. 4222 is threatening as an attack if the full backs are threatening in their overlaps. Dalot is the most dogshite right back I've seen wear a United shirt, and this is after Darmien. Telles outside of a good cross is doing very little too. If you put anyone, say Regulon/Tierney/James/Alonso/etc. in their roles then I think the XG bumps up maybe by an entire digit than what we normally see.