Manchester United should have sold this player a long time ago, because at Manchester United he didn't contribute much to the game and even more defeats that he made which was very detrimental to the team because it could be that the mistakes he made made Manchester United have to suffer defeat. Regarding Haaland, honestly I don't think he will leave Manchester City so quickly, because he is one of the mainstay players in the front line and he can also be one of the players who can finally present the Champions League title for them. Barcelona? I don't think about that, because the finances they are facing do not support them to recruit players who have expensive prices, because surely if Manchester City sells Haaland they will not let him go for a cheap price.
Harry Maguire is always rumored to be sold every season, but strangely he is still at Man United and he even often plays as a starter. His performance is also not as bad as before, so if they really have to reduce the number of defenders, I think it's better to sell Victor Lindelof than Harry Maguire. Likewise, with Erling Haaland, I don't think he will leave Man City anytime soon (at least in the next 3 seasons) because there really is no strong reason why he wants to leave Man City.
Well now there is actually an improvement in Harry Maguire's game, but his contribution is still not that big, so I think the decision to sell this player is not a bad decision. On the one hand, there are still many players who have not shown their best game with Manchester United, so this is also a challenge for them to be able to restore the performance of several players.
One more thing that makes me wonder, why does Erik Ten Hag like to call players who previously worked with him, because the players he brought back were not very effective. There are many problems that must be solved within Manchester United, so this must be handled seriously if they want to return to their former glory.