I agree with your views on comparing Osimhen with Lukaku, two very different players in regard to their age and development. It's fair to say that Osimhen brings a lot of potential for future growth and performance. Each player indeed has their own unique strengths and weaknesses, and their value to a team cannot be simply compared.
Players who have potential when they are in a team will certainly be the difference with other players because players who have potential in every match will be key players for their colleagues even though the coach must care about all players in every line in order to continue to improve the strength of his own team. This season Napoli has again shown its ability through existing players including Lukaku in it, but Napoli still has to be more consistent and Lukaku also still has to work better during this season, as well as Osimhen in other leagues.
Basically Lukaku and Osimhen are great players but unfortunately, Conte only chose one of them and I think it's not so right even though so far Conte has succeeded in making Napoli get good results. Because of course, if Osimhen is still maintained then it will be good for Napoli to rotate players, especially since Osimhen is still young which is certainly good for the long term, because in the previous season Napoli also extended Osimhen's contract.
At least, this factor also disappointed me, because if Napoli didn't want Osimhen, then there was no need for Napoli to give a new contract and salary increase at that time. Because after all, if in the end Osimhen is not needed by the team, then it is better for Napoli to sell him at that time after getting the scudetto, but Napoli kept Osimhen and made Osimhen's career bad by throwing Osimhen away like that.