Osimhen probably doesn't want to be at Napoli anymore because Napoli don't play in the Champions League competition, I think that's a natural thing for a player like Osimhen, it's appropriate for him to go to a much stronger team.
Meanwhile, NApoli's plan to recruit Lukaku cannot be separated from Antonio Conte's wishes because Conte is quite happy with Lukaku and I think from what has happened in the past Lukaku's quality will suit Conte's coaching style quite well.
Even though Lukaku's performance has really declined at the moment, I think every coach has his own point of view and we have to respect that.
Osimhen has actually extended his contract with Napoli at the end of last season, but strangely he also does not rule out the possibility of leaving if there are indeed other teams that will recruit him, I think the contract extension between Napoli is done only to include a big release clause in his new contract, especially since PSG was rumored to be very interested in recruiting Napoli this season so that at least later it will give a big advantage to Napoli, Next season Napoli will not play in the Champions League so that Osimhen is quite disappointed and napoli allows him to leave for another team, but PSG, who was previously quite interested in Osimhen but is now not in talks with Napoli, in addition to PSG,Chelsea have reportedly also withdrawn from their desire to sign Osimhen next summer.
Conte arrival will of course give a new color to Napoli's performance next season, and even Conte has prepared several names of players that Napoli must recruit to be able to compete next season, including Lukaku, but reportedly the deal is very difficult to happen because Chelsea wants Napoli to pay 37 million euros, while Napoli wants a trade-in option between Osimhen and Lukaku and Chelsea rejected it.
Lukaku and Conte have worked together so indeed Conte understands the characteristics of Lukaku game so far, although indeed Lukaku this season is not in his best form but it seems that Conte has a strong reason to recruit him and of course maybe Conte has the right solution to restore Lukaku performance later if he plays for Napoli next season.