This talk of playing up United like they are Man City or Liverpool is silly. Yes, we have injuries and yes, we would like Rudiger and Hudson-Odoi to be fit right now but we still have enough good players to get by this game - and beyond till they return. Whether we'll win is a different debate.
If you fear their new players, then god help us all. United buying AWB and Dan James is just like us taking Mount, Abraham from our academy/loan army and putting them into the team. Different positions and all that but same point applies. The only difference is United paid big money while we didn't need to. They might be talented but they are still young and don't exactly scare me right now (doesn't change either even with Maguire). Would have been a different story altogether had they signed Cancelo, James Rodriguez etc or established players.
Also, how many is plenty? We only have like 3 youngsters in the squad right now. Mount, Abraham and Pulisic (James and CHO excluded due to their injury). Is that plenty? United will likely have AWB, James, Greenwood. We're almost identical in number of young players in the team.
And worth remembering that United ended last season even worse than us. I know we won the Europa League but they finished 2018/19 with something like 2 wins from 12 games. Their key players were horribly out of form, players who want to leave this summer etc. So just like us, they have uncertainty hanging over them and several things to prove this season.