Last I checked Osimhen is still in Europe. He plays for Galatasaray in Turkey and he's performing very well there. He's among the top scorers in the league and he's on course to help them win the league for them. He's not in Europe's top 5 leagues but he's still in Europe and still has a contract with Napoli.
I think it's a good thing his market value dropped so it will be easier for the team to sign him. Chelsea are feeling the consequences of not signing Osimhen last summer. I belive other top clubs will go for Osimhen or even Chelsea might go back for him.
Osimhen's release clause has already decreased a lot as a part of his contract extension with Napoli. His price dropped so much not because of how bad his performance. It's to ensure his clause has sense price, and he can leave anytime.
I saw some top clubs such as Arsenal, MU or even Chelsea strongly linked to him. However, there's no concrete development about which club has contacted his agent to buy him out. I hope Chelsea will contact his agent, then sign him asap .
The reason why his release clause declined was just because he isn't playing in one of the prominent clubs in Europe otherwise instead of reducing, he could have even increased more in value because of his performance at Galatasaray, had it been those performance are in Napoli or any other famous European teams there is no way his release clause would not have increased. On the other hand, it is good his release reduced so that he can be affordable and more clubs will begin to show interest in him and from how the rumors are spreading, he could probably join Manchester United. Arsenal and Chelsea are not serious because if they do, they could have been in the forefront negotiating about the player and moreover, last time when Chelsea developed interest in Victor Osimhen, Napoli placed him on a very huge clause release which made Chelsea to withdraw so even now that he is in the picture of Chelsea, they may not still sign the him.