No doubt Hojlund is a good striker but isn't good enough to handle the pressure at Manchester United and bring the positive change Manchester United fans have been longing to see, so I agree with you that he should go back to the Italian league and develop himself into a better and more mature player before he can play in the Premier League.
A good striker and a world class striker have big differences like consistency and ability to deal with pressure and expectation well or not. Hojound can play well at a small club but might fail at bigger clubs like Manchester United. Many players fail with their adventures in big clubs and Hojlund looks like another failed striker under pressure and expectation.
Manchester United can stay calm and give Hilojlund one or even two more seasons. After giving him enough patience and chance, if he still fail to improve himself and contribute better for the club, Manchester United will have no reason to trust him more and actually need to find a better striker to replace Hojlund.
I don't think that it's because Manchester United was a big team that was why he was not able to deliver the truth is that any player coming to Manchester United will not play at his best because the environment in united is not a good one that players can do well