Harry Maguire is quite a talented player. However, he often makes big mistakes between matches, and Harry Maguire's errors have cost Manchester United several matches. Defenders have to play very carefully. But Harry Maguire is not careful. Although he was talented, he failed to develop the talent properly. Harry Maguire was not experienced enough at 30 years old.
Harry Maguire is not totally bad and has his talent as well as weakness that must be covered by his team mates and a team tactical operation. He can play well if he is put into a system that can support him, cover his weakness and help him to show off his best strength.
In Manchester United, he does not have it and he also carries very big pressure because of his high transfer fee from Leicester City to Manchester United. His performance for England is difference than what he shown in Manchester United. However he is not a top-notch central defender and far lower quality than legendary central defenders years ago in Premier League like John Terry, Rio Ferdinand, Sol Campell.
I don't think Harry Maguire is a bad defender either. But he made several big mistakes in United's squad. This is why Manchester United fans don't like harry maguire. And harry maguire was the victim of many trolls. Perhaps for these reasons, manchester united coach Ten hag is not interested in keeping harry maguire in his squad. However harry maguire's future is uncertain. Now it is unlikely that any team will take Harry maguire at a high price. Manchester united management is not interested in giving Harry Maguire on loan. Harry Maguire is likely to stay with United next season. But the Ten Hag are unlikely to keep Harry Maguire with their main squad.