If the Napoli administration chose him, I'm sure he could have done something like this after a long research. This year is a year with higher expectations and Garcia should be aware of this. He has to plan for next year's transfers now. If they want to win the Serie A championship once again, they have to make a good strategy.
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.
It is quite obvious that we are going to see Spaletti come back again, but the fact that he had a high tempo life that asked so much of him and the amount of stress that he had to endure was very high.
I know that this is normal for the job, you get millions and in return you work very hard, there are people in this world that deserves it more, like surgeons who operate and save human lives, and yet managers and players get, it is the old argument I am not going to repeat that again, but the reality is that it is still a tough job and if you have millions, why endure such thing? Napoli fans, players, officers, owners and everyone else would have look to him to get the title again, and he just wanted to not have that stress anymore and rest.
I think Spalletti decided to take a break because he knows that he has to take a short break from time to time to work out what strategies can be used to bring his club to what Spalletti wants.
Maybe because Spalletti felt like he failed to take Napoli to a higher level like the champions league.