Antonio Conte also seems to really want Lukaku more than Osimhen. Maybe it's not because Lukaku is better than Osimhen. It's just that Osimhen doesn't seem comfortable at Napoli anymore.
Reason Osimhen was uncomfortable in Napoli only at that time when the president of Napoli often replaced the coach made Osimhen feel that adaptation to every new coach made him very bored.But after the arrival of Conte coach, I am sure Osimhen will return comfortable because he also needs experienced coaches like in the Spalletti era who can develop his career with Napoli as the most scorer.
And for Lukaku, I will not agree if Osimhen position is replaced by Lukaku and the reason is quite simple if Lukaku is only a big body striker but in terms of expertise, I believe Osimhen more.
Source : https://www.transfermarkt.co.uk/victor-osimhen/profil/spieler/401923
Osimhen got 15 scores from 25 matches while Lukaku only got 13 scores from 32 matches and from here the difference was quite clear.