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.