A huge problem Maguire has had over the past season is that he has seemed to be caught in two minds between stepping out of the defensive line to act as an aggressor (closing down players and attempting to win the ball) and holding position to cover off attacking runs. This has often meant he won't fully commit to either course of action, and as a consequence leaves gaps for players to run into without closing off passing options for the player on the ball. The first Liverpool goal at Anfield, where Maguire fails to properly close down Mane, is a perfect example of this.
This is why I make the argument that Ten Hag's high-line will probably help and not hinder Maguire. Within this setup, Maguire will almost certainly be told to be the aggressive centre back (this is what he's best at and we don't really have another regularly fit centre back who can do it) and, with a clear strategy for the defensive unit, we should see fewer moments where he's caught in two minds.