Napoli are working on a contract extension for Osimhen. He has drawn the attention to himself quite much after his amazing performance in the previous season. But as his cost is going to be quite high for the other teams interested in signing him I don't know if any team would make an official offer. Napoli must be asking for at least 130 million euros.
His salary is nothing for a player like him now and this gives Napoli an advantage to convince him for an extension. I assume he would demand a couple of million euros rise in his salary and I would expect Napoli to accept that. As he has 2 years left there Napoli had better secure his future there.
Osimhen is smart enough to know that he will stuck in Napoli like Harry Kane in Tottenham if he sign a new contract with Napoli. Napoli can increase his salary but I believe that Osimhen wants more than salary and he will try at bigger clubs to chase for bigger titles like Champions League and want to play in bigger leagues like La Liga or Premier League. So Ligue 1 and PSG likely are not interesting destinations for Osimhen in this summer.
Yes, Osimhen situation will probably be like Kane at Tottenham, and he will stay at Napoli for a long time if he accepts a new contract from Napoli. Previously Osimhen dreamed of playing in the premier league, but unfortunately no club has been able to accept Napoli request due to the high price. They chose to retreat but it's only a matter of time, maybe they will come back for that man. This new season I actually believed that Osimhen would stay with Napoli, considering the term of him contract too with that club until 2025.