I don't think Harry Maguire would have been called up to the England national team if he was overrated. That's why it might be a bit harsh to say it's exaggerated. He definitely has talent and it wouldn't be right to claim otherwise. However, he is very error-prone and this causes big problems in the teams he plays for.
Harry Maguire was once the auto choice of England national team and Manchester United there was no match where England or Manchester United announced without him but recently due to his performances and other factors he is not getting a place in the regular eleven. Manchester United tried a lot to sell this English defender this season but no club showed interest in taking this defender due to which Manchester United was forced to keep him in the team. Harry Maguire captained Manchester United but his poor performances last season led to him being dropped. He is still being given a chance in some matches, if he is not able to use that opportunity, then this English defender may be dropped from the team.