I don't think Napoli are ready to lose their keyman to any elite club this summer, they've solid plans for the Nigeria international and keeping him would be their absolute decision.
You may be right because we have not really heard anything in regards to that case about the Nigerian player in Napoli, perhaps it could be that Napoli has realized that the player still have a lot of things to offer them if they decide to keep him, well considering the condition of the transfer market were every club is currently trying every means possible to make there club strong no club will like to sell there player that's still very active on there front line, so I agree with you because with the look of things I don't think he will be leaving Napoli this season maybe if they are to sell him it will be after this upcoming season because the competition is too much on this season.
I personally believe, this problem is because Conte does not want Osimhen and then, Osimhen is available for sale but at the same time Napoli still want Osimhen to stay. Because anyway, with the Napoli factor extending Osimhen's contract last season is also at least proof that Napoli want Osimhen to stay at Napoli longer. And also, last season also at the time of the contract extension, that Osimhen did prefer to stay at Napoli rather than leave.
Because anyway, last season also the fact that several elite teams have been interested in buying Osimhen but anyway, because Osimhen and Napoli have agreed to continue to cooperate, and then the contract extension also occurred. But unfortunately, Napoli's performance also declined and Napoli appointed Conte as Napoli's new manager as well as the fact that Conte preferred to buy Lukaku rather than keep Osimhen. Thus, I believe that if Conte had not made such a statement, then maybe Osimhen would still be fine to be at Napoli.
You are right, with the look of things I think Conte is the reason behind everything, however considering how new he is in the club he shouldn't make some kind of decision especially the ones that involves selling a player because he has not really work with the club to be certain of how the players perform, so for me I think what he should have done is to give Osimhen a chance to prove himself instead of that sudden dislike, however the negative aspect of it is that since Conte has a wrong perspective about Osimhen it may likely affect the performance of Osimhen, though Lukaku is not a bad idea but since Osimhen still love to play with Napoli I think he should be allowed to stay more longer because he is still an assets for the club.