PSG most likely have better contract terms, and I think better prospects in the Champions League than Napoli. If a football player feels that he wants to move on, then there is no point in keeping him. I don’t understand why PSG is a bad club for a career, they are the undoubted leaders in their championship, that is, this is an opportunity to get champion medals from another championship. In addition, they always strive to win the Champions League, and often get quite far. Of course, Ligue 1 is not as competitive a championship as the Premier League or La Liga, but you need to evaluate the capabilities of the club as a whole, and not just within their championship.
In my opinion, there is a big difference when you play for a medium team but are in a competitive league with a big team but are not competitive league at all, so indeed the situation and conditions will be one of the factors that really determine a player desire to join, but it is different with osimhen who really wants to join PSG but actually faces big obstacles with the high prices set by Napoli at the moment, we all know that Napoli chances of competing in Serie A are very small because they must to compete with many big teams and this is different from PSG which In fact, they have dominated Ligue 1 all this time, so as you said, PSG is like the king who has been replaced in Ligue 1.
PSG is fighting hard to get their first Champions League trophy at the moment, so Osimhen can use PSG as a stepping stone to get a better career and finances in the future, Joining PSG will of course guarantee Osimhen can continue to win domestic league trophies and I think there is no other team in Ligue 1 that can continue to be guaranteed to qualify for the Champions League every season apart from PSG at this time.