In my opinion, in terms of career performance comparison, Lukaku is much better, but looking at the current season comparison, Osimhen is better, but Osimhen has not yet proven whether or not he can be a good player after leaving Napoli, something that in my opinion could be a disaster for Osimhen if he leaves Napoli. I say this because at Napoli he is the center of attention, even during games the tendency of his teammates is to pass the ball to Osimhen. But that will not happen when he plays for a team like PSG, then he will gradually lose importance, which is why in my opinion it would be good for Osimhen to stay at Napoli until his contract ends and improve his performance even more so that he attracts the attention of big teams in the Premier League, I am talking about Manchester City, Arsenal and Liverpool. Teams like Chelsea and Manchester United would be career destroying.
First, your stats for Osimhen's goals is not accurate. He has scored 76 goals for Napoli so far and he scored 17 for Lille in France, not 14, but that's btw.
Since Osimhen has not played up to half of the games Lukaku has played, you can't compare just by goals. You have to use the goal ratio. If you notice Lukaku played 278 games in the epl and scored 121 goals, and Osimhen has scored 76 in 108 games, that shows that Osimhen's ratio is more impressive than Lukaku's.
If you compare Lukaku's serie A to Osimhen's, Osimhen is still better because I'm pretty sure 76 goals in 108 games is better than 70 goals in 129 games.
When people say Osimhen hasn't proven himself, I don't understand what that means. He scored 17 goals for Napoli despite them having one of the worst league seasons in a long time, he scored 31 before that. We've watched him perform time and again but you still say he hasn't proven himself, what more do you want him to do? And don't tell me the "because he has played in the epl" bullshit, because currently, the serie A is just as difficult as the EPL.
In my opinion, Osimhen will do just fine in PSG. They don't have a striker better than him and they don't have Mbappe anymore that the whole team looks up to. Osimhen is not the kind of striker that waits in the box like Lukaku, so he'll excell in a lot of big clubs. As long as the club has good wingers and midfielders, he will be fine. And I PSG he'll have way less pressure on his shoulders and that can be better for a player.