He is so dependent on Osimhem that the chances of him joining Napoli are very small.
There are no funds available when Osimhem is not bought by another club and I think the option is to play in the Saudi Arabian League.
I am not surprised about Lukaku's situation right now, he is no longer a top striker and Chelsea want to get rid of him as soon as possible. Victor Osimhen to PSG is becoming concrete and we may soon see the deal getting sealed, that is the only way Napoli can be able to fund Lukaku's transfer and sign him from Chelsea.
As for Osimhen, it will be a great move for him to join PSG, they just lost Mbappe to Real Madrid, and Osimhen will be a good addition to the team, he won't be a direct replacement for Mbappe, but he will definitely bolster the team.