I agree that Leao might be a better option for Manchester United than Lookman. The two are good players but Leao proved himself in AC Milan many times and could adapt perfectly. I have some worries that Lookman will be the new Victor Osimhen, he needs to learn from his Nigerian teammate who was once, one of the best players in a season then he faded.
What's wrong with Osimhen? Osimhen is still a top player, he only had a fallout with his team and Lookman isn't having that problem. Moreover Napoli and Atalanta do businesses in different ways. Napoli is a difficult club, but Atalanta won't do that to Lookman.
Lookman has worked for Atalanta so I don't think they'll make things difficult for him to leave.
Osimhen hasn't faded, he's just playing in a lower team and league and despite that he's still playing top football. Lookman is a good player and he deserves to be in a bigger team like Arsenal. Not like he can't succeed in another team but Arsenal fits his profile.