Osimhen is a young player and he can't be counted as a stable player, he just had one good season with Bapoli and we can't make sure if he will have a good performance in other teams like Chelsea or other teams, on the other hand, Napoli asked him for a huge amount of money and paying this money for Osimhen can be a risk for any team.
Osimhen is a young player, but i don't get what you mean by he can't be counted as being stable, the young man is undoubtedly a lethal striker and even though he had his best season last season, he has always been a very decent player since he burst onto the scene. Osimhen is definitely not going to Chelsea, they are not in the CL next season and they are a club in transition currently.
I think Osimhen should follow in the footsteps of Jude Bellingham and join Real Madrid, but not this summer, maybe the next one; the best option for the Nigerian marksman is to remain in Napoli for at least another season, that will help him to assert himself more as one of the best strikers in Europe, and thus take his next step with more confidence.