Juventus got Jonathan David for a striker, hence why they didn't get Osimhen. Sure you may think Osimhen is better, but the difference is that you need to pay 20 million a year on Osimhen plus 75 million transfer fee, whereas David was free, and cheaper salary. They already spent 100+ million, and with their sale, they are at minus -50 million right now.
I guess the best case for the time being is the recovery and if they can be safely handle the finances, they will do fine. I get that it may not be easy, but they can definitely control this and should be happy about it. I get that it may not be a big deal to finish 4th or whatever, but it is going to be horrible if they pay more, spend more, try to be first, and then fail.
Napoli never ever wanted to sell their key player to their rival. That's why selling him to the Juve is just a dream. They even restricted him on their agreement with Galatasaray to never sell him to the serie a club. That's why his move to the Juve was impossible.
Napoli will never let himself be weakened because he knows that if the players join another team they will be weaken and their performance will also be known. There is also a reason for this that other teams think that they can sell him for a certain amount of money so that they can get this worthy player. The Napoli has made a very good decision because Galatasaray change a lot of players and they have such players and Juve is a good player and has take their team to a lot of progress. Apart from this this player is get a lot in this team that he wants.