The Osimhen transfer will create significant funds for Napoli. If he is to leave the team, his income must be at least 100 million Euros. There are few teams in the world that can offer this (I don't count the Saudis

) That's why one of the few alternatives is Paris SG. If I were him, I would go to League 1, PSG, thinking that it would be better statistically, but I know that he loves competition and I think Osimhen will choose the Premier League. It is a pleasure to watch the Nigerian. I think he would fit in better with those great players.
If Osimhen really likes competition, why last season did he reject many offers from European clubs? especially Chelsea but Osimhen chose to stay. Now like it or not imo the most sensible option is to take PSG offer, staying at Napoli doesn't guarantee that you will get enough playing time. What is clear is that Osimhen needs to get out of his comfort zone and challenge himself to prove that the price tag above 100 million Euros is worth it. PSG is the only club that is ready to provide guarantees for the main squad, at least PSG will return to the UCL in a different format.
To be fair to him, he was still under contract and as long as the team doesn't want to sell the player there is not much that he can do. He could have forced his club to sell him, and would say he will not play in the games unless he is sold, but that would not be easy and it could have caused further problem for his career. So maybe he did wanted to leave, and we just did not know about it, he may have done all he could without making a big scene, but if the team didn't want to, then what could he have done about it?
Napoli wanted 100+ million for him, and to be fair that was always way too much, who would pay that much money for a player who had one great season? The reality is that he worths somewhere around 60-70 million range if you ask me, nothing more than that would be realistic and he would be staying at the club. The real question will start when his contract is nearing the end, if he wants to really leave, he won't resign and will go to another team.