Actually there is no guarantee either but seeing from the tension of the game in Ligue 1 and Serie A which is not too different, it is possible for Osimhen to develop better in Ligue 1 with more complete resources. At least if he moves to PSG there will be several trophies that he managed to bring as his achievements because until now there is not even one that can be considered a rival for PSG when talking about domestic competitions.
His ease will be more pronounced at PSG than if he goes to the EPL considering Chelsea also wants him because his future is more uncertain in the EPL than Ligue 1.
At the moment Osimhen is still very able to improve his performance especially he is still very young so I think the chance to develop in Ligue 1 (PSG) is still very possible for his individual achievements rather than him going to Chelsea.
Osimhen has the opportunity to win a trophy every season if he joins PSG and plays in Ligue 1, apart from that, Osimhen also has the opportunity to play in the Champions League every season. Osimhen deserves to consider these two factors. If he leaves Napoli, moving to Chelsea is not a wise decision for a bright future. For now and next season, Chelsea seems to have difficulty competing with other top teams in the Premier League, and it is certain that next season Pochettino squad will again miss appearing in the Champions League.
So it stands to reason that Osimhen would be better off going to PSG if the other offer that comes in is Chelsea. Apart from that, Osimhen performance this season is not optimal, it is very much lower than last season, especially since he suffered an injury while defending his country competing in the AFCON Cup. Whoever is interested in recruiting Osimhen, the eccentric President of Napoli will not let his best players leave for a cheap price. PSG and Chelsea don't seem to be having problems regarding money, but the final decision is up to Osimhen.
But there are some conditions that are not forced too because there will definitely be a guarantee that Osimhen can get trophies every season and be in the Champions League every season but he also has to accept the fact that his situation and individual achievements are just like that and its difficult to make a real improvement for his individual performance when he is at PSG because he cannot get anything more than what he will receive in Ligue 1.
In contrast to the EPL if he shines there its certain that there will be a lot more queuing to get his services its just that it is proportional to the performance he has to do because in terms of level the EPL is clearly very much better than Ligue 1.
Now it depends on Osimhen and how their agreement is actually if in the end Osimhen expect money and a less difficult situation then PSG is the right place but if indeed he wants a new challenge including changing the club which is currently in poor condition then Chelsea is the real answer in this case.
PSG will provide an easy path but no matter how good his performance will be then it will be considered normal because it is Ligue 1 but if you really want to find a challenge with a more complicated path but there is no guarantee to be able to play impressively then indeed the EPL is a worthy place .