It looks like Napoli are quite likely to keep Osimhen this summer. At least for now. Because there is no rumour regarding him to sign for another team these days. However there might be a chance for PSG to think of bringing him depending on Mbappe's situation. When they lose a player like Mbappe they need to bring another top player to try to make up for that.
Vlahovic has been rumoured with PSG maybe but in this case I think PSG can change their route to Osimhen instead. PSG are going to get 300 million euros as a transfer fee from Al-Hilal if Mbappe signs for them. They can surely use this money to sign a player like Osimhen.
Because Napoli has already made it clear to all clubs that Osimhen is not for this summer, Osimhen has transformed Napoli into a team that they haven't been in many years, and Napoli still believes that if Osimhen is there, they will still win the league once more. As for PSG, I don't think Osimhen will come to PSG because of the way PSG holds their players without allowing them to leave the team whenever they please. I am aware that PSG can make any offer to get any player of their choosing, but if they continue to treat other players the same way they treated Mbappe, nobody will want to join the squad.
We all know that money can change people's minds and can also make things go the way they want, but sometimes money can't change some people's minds. Due to the rumours I've heard, mbappe hasn't said anything about going to Al-Hilal. I believe that Saudi Arabians view sports as something that if there is money involved, they can have anything.