If osimhen's price is continue to drop, then club will be caring about that. 
In the end, buying lukaku from chelsea is not a bad option, and im sure this can be an opportunity to push osimthen to give more.
Osimhen should be retained instead of selling him at a cheap price, especially if his price decreases because his performance may also appear to have decreased playing with Napoli last season which didn't perform well, although Lukaku, if he can be bought, should be able to partner with Osimhen, it's not bad enough, he might even be able to make a game. can be more interesting and provide color for Napoli next season, Conte should be able to find an alternative for Osimhen, this can at least make him improve his game even better and make his performance also increase and not continue to decline so that it can make his value continue to fall. In the end, buying lukaku from chelsea is not a bad option, and im sure this can be an opportunity to push osimthen to give more. The manager of Napoli now Conte seems to be more interested in bringing Lukaku to the Napoli team because has not for once made a comment insisting that he wants the player to be retained in the team instead it was rumored that the coach made it open that osimhen is going to be his second choice if he's going to be in the team.
Osimhen is far younger than Lukaku despite Lukaku having more experience than Osimhen but the performance of both players can not be compared because age has affected the performance of Lukaka. I will suggest that osimhen should get another club instead of remaining in Napoli because being their means he's not going to be appreciated enough even when he helped the team to get better and won the league title for them after a long time that the team has not won the title