Ah, fair enough.
Osimhen had scored 13 in the league, which of 2 were penalties. He played around 500 more minutes in the league than Højlund had.
What I mean when I say Højlund has shown more at 20 than Osimhen did, I'm talking about his movement, hold-up and link-up play. He also operates surprisingly well in little space and has great instincts in the box.
Osimhen, while stronger, much better aerially and generally more established didn't show these characteristics for Lille at 20, and still hasn't developed his link-up play at all. Another factor to consider is that usually it is easier for a forward to score in Ligue 1 than Serie A because teams are more about attacking than defending, which leaves a lot of space to operate in. Serie A on the other hand is generally very defensive and as a striker, you'll have defenders all around you.
I agree with the rest of what you've written but the bolded part I don't see at all.
Hojlund is quite adept at hold up play and he seems like a terror in space, on the break, and in broken situations after a turnover. I've seen very little across a number of video compilations to suggest that he has the ball skills to be effective either solo or as a combination player when the spaces get tight or very effective against organized defenses.
This has come out in every touch videos too but just to take one example, watching a compilation of his league goals in Serie A just now, what I see is this:
-Keeper mistake, slides to steal and score
-On the break in a broken field situation, running at a disorganized back line
-Another breakaway 1 v 1
-Defense is defending deep, gets a good scrappy goal
-Does really well here against a defense that isn't tight but is relatively deep, beats a man and scores back across the far post.
-Running on the break again into the six yard box against a broken defense scrambling to get back.
-Another 1 v 1 on the break.
-Runs behind a deepish defensive line for another 1 v 1
-Again running in a broken field situation past a disorganized defensive line
-Another situation, probably off a turnover, where he gets just past a disorganized line that is scrambling to get back and pokes in.
-Great hustle to block the keeper's pass right into the net.
Things that I didn't see in any of this goals: He never scored with his head, never scored off a set piece, only scored once when having the ball at his feet with a man in front of him and needing to create a yard of space to get off a shot, never scored after a quick 1-2 passing combination with a team mate, probably only scored one goal against a defense that had more than 5 or 6 players around the box and was defending in an kind of semi-organized way.
None of this is to say that he can't develop the ability to score in these other ways over time. But he's isn't exactly Romario in the box or with the ball at his feet.