Actually, Manchester United are serious about releasing Harry Maguire in the current transfer market. It's just that no one really wants Harry Maguire yet. West Ham actually made an offer to Manchester United. But it wasn't an offer to buy Harry Maguire. But West Ham only made an offer to borrow the former Manchester United captain. And of course Manchester United immediately rejected the loan offer from West Ham. Because Manchester United don't want to lend Harry Maguire. But Manchester United want to release him in full. And the latest rumor is that Chelsea are also interested. But I also doubt that these rumors will come true.
I don't think there are not any Primer League teams interested for signing Harry Maguire but highest transfer fees offer from Manchester United make it difficult for signing Magurie. West Ham United linked as serious teams want to sign Maguire but he has announce about loyal with Manchester United and stay until his contract over although can't guarantee with regular position next season. Its difficult position for Harry Maguire right now, after loss position as captain teams, he has chance loss position as regular player for next season.
Actually, Harry Maguire have looking for new teams who guarantee with more minutes playing although not participants in Champion League, Chelsea is the best option for him but he need to ask Pochettino about chance as regular player or not.