Harry Maguire will always stick tight like glue and I think he'll only really leave Man United when his contract runs out. It seems that he still has the ambition to prove that he can improve and get his place back, but I guess this season will be no different from the seasons he has been through. What was clear he had to mentally prepare because most likely he will again face the pressure.
Manchester United were stupid to buy Maguire and gave him very high salary but the player is smart to recognize that he will receive same high salary if he leaves Manchester United and joins any club in Europe. With his poor performance for Manchester United, big and rich clubs in Europe will no longer want to have interest to buy Maguire.
His only chance to receive similar or better salary is from Saudi Arabia but so far, no offer, no rumor about interest from Saudi Arabian clubs. If such opportunities won't come, Harry Maguire will stay with United, complete his contract and fill his pocket.