I don't think Antonio Conte has any problem with Victor Osimhen so even if he brings in Romelu Lukaku it's still not a bad decision but I prefer Victor Osimhen to Lukaku because Osimhen is more of a tactical player than Lukaku.
negotiations between Napoli and Osimhen were quite tough regarding him being a high-rated player in Serie A. There was no problem between Osimhen and their new coach, Conte, it's just that Napoli's conditions required them to let go of their mainstay player. Meanwhile, Napoli needed other costs, especially after they signed Conte, who is also a high-rate coach in Serie A. Like it or not, because negotiations were like that, and Osimhen also wanted to leave, Napoli decided to sell Osimhen. It's just that so far price negotiations with several clubs have been quite tough. It is possible that Osimhen will eventually go to Chelsea with the option of a swap deal for Lukaku. However, the negotiations are still not that smooth, so this has made Napoli reduce the release clause.