Maybe Erik Ten Hag saw talent while at Atalanta even though it was only 1 season with Atalanta but Erik Ten Hag has seen so far that even with injuries Højlund was signed by Manchester City and I don't doubt Højlund because he seems to have talent at a young age.
That is the selfishness of Manchester United players is still difficult for Erik Ten Hag to overcome even though we have known how other players do the same, but do not know what is in Ten Hag's mindset because he is still difficult to manage the squad that is still surrounded by other player problems such as Jadon Sancho.
I think Erik Ten Hag believes in Rashford more than Højlund, although my own assumption is that Højlund's game is better than the current Rashford, he has a selfishness and wants to control the ball to score but does not think about the chances of other players.
Every coach has a reason for signing a player, they don't go about signing liabilities, they sign players as a result of their performance and then the fact that they see them as potential assets to their team, and sadly after being signed, the players will now lag behind in displaying up to expectation, then it'll seem that their signing was a regret or mistake but it's not true.
For United striker signee, he seems to have had better ball displays than Rashford, although he was signed as a result of his good performance in his last club, even though he isn't doing up to that same stance with United, he's at least trying and for Rashford who's been in the team for seasons, his performance this season has been so poor but still Ten Hag still allows favouritism to set in which is wrong in a team, Rashford needs some scolding and a very huge competitor for his spot, I believe that's the only means he'd have to use to try sitting up in his game.