I am almost sure that Osimhen will leave Napoli. You will have to pay a lot of money for it. Chelsea are ready to pay this money and they can handle this burden financially. The biggest advantage for Chelsea is that Osimhen is very interested in playing in the Premier League. I am sure he will achieve success with Chelsea in the Premier League.
Osimhen base price is actually around €120m, it is according to transfermarkt. But Napoli president always tells us non sense price for Osimhen. It is likely no interest to sell Osimhen to other clubs. The latest news I read, De Laurentiis will only consider an offer above €500 million for Osimhen. I think no club wants to sign him at that price, it is too crazy. Even I doubt Chelsea has an interest to sign Osimhen if Napoli only wants the offer above €500 million.
It would be difficult to see a club that would sign Osimhen for €500 however if it finally happens it's going to make him the player with the all time highest transfer price, but I doubt if that would happen cause even the Saudi's wouldn't want to spend that much to get him and Osimhen In person wouldn't want to over to the Saudi Pro League yet, cause he still has lots to achieve in the European competitions.
The inflation in his release clause is to scare off other clubs that would come in demand for him by summer, just like PSG did with Mbappé this summer, it's obvious that they've got no Interest to sell him, but I feel they'll be forced to reduce their asking price to the normal €120 or 150 if Osimhen decides to leave the club and try to force a transfer out of the club which is very possible by summer,Chelsea are really in need of a striker but I don't think it would be Interest for him to move over there.