I don't know why Luciano Spalletti will just turn his back on Napoli when the star is shining brighter, I guess the guy did not believe in the second time of a good performance like this season, so, he stylishly exited. As for Rudi Garcia, I don't know much about the guy but I believe him as an old player and coach that he would be able to deliver in his own little way. I will not cast much doubt in a good performance of Napoli in the next season, but that is only if they do not eventually sell Victor Osimhen.
If Spaletti wanted to return to Napoli, he would never have left this team. He may be bored with Napoli or he may be waiting for an offer from a good Premier League team. It was a great achivement to make Napoli champions and they did, it may be next to achieve even greater success.
To leave a champion team, you need to have a better goal. Otherwise, you would continue to work in the same team.
Maybe he will want to go somewhere in Saudi Arabia and earn money, who knows
Obviously he should aim to be at a higher level when he joins another team after leaving Napoli. But until now I haven't heard rumors about Spalletti.