He was one of the best CBs in the Premier League at 26 years of age at Leicester, when we bought him. Not to mention that he's English. He then continued to be one of the best centre backs in the league in his first two seasons at the club. He was abysmal in 2021/22, but that goes for every single player that was part of that squad. Since then, he's been the same player as before, but has been out of favor under ten Hag.
If you look at how much the van Dijk transfer raised CB fees in the last 5 years: Gvardiol, de Ligt, Fofana, and Dias all went for similar or bigger fees in the case of the Croatian.
He's really not too dissimilar of a profile AND level to de Ligt or Dias. If Maguire went to City and we got Dias or de Ligt instead in 2019, he would have been considered a top 5 centre back in the world for the last 5 years. However, he made the mistake of joining a dysfunctional team, club, and environment which got his reputation ruined.