Manchester United convincing Atalanta to accept their price is absurd, because one would not expect such a competitive elite team to come imploring with an average club to sign their star. You are correct in these words; Italian teams always offer fixed fees for their valuable players. When an EPL club comes looking for a player, the player who piqued the interest of the EPL club becomes an instant star in his club. This is not their first or second time doing this; they've been doing it for quite some time. Don't get me wrong: their players have wonderful traits and a high profile rating, but that doesn't mean they're significantly better than the EPL players in the picture in question.
Yeah, even a great player in domestic league can't perform in Premier league, what about Hojlund where he wasn't perform in Serie A. Manchester United don't really need to sign a new striker, they currently have enough strikers and just wait until few matches to see if Rashford, Martial or Garnacho aren't give a good contribution.
If Manchester United don't mind to spend 90 Million Euros, they should get better player like Harry Kane, Leao etc.
Manchester United's striker shortage is not a big problem right now, I think. Rashford can be considered for that area. If they can get Harry Kane it would be a nice extra deal but I can't imagine Tottenham selling him to a competitor. So I think this possibility is slim. But Hojlund will strengthen them, that's for sure.