Antonio Conte is certainly one of the best coaches around, of those who have won. However, Jose Mourinho was also like him and now he is struggling a little to make his strategy work. Many have understood his schemes and play in a way that invalidates his playing style. It could happen to him too, we'll see if he can do well with Napoli.
If not supported by a qualified squad or players, I think all coaches will also have difficulty building a team, as is the case with Antonio Conte now.
Napoli has been quite depressed last season, so don't expect too much from Antonio Conte to immediately be able to develop Napoli's performance in his first season. I think a quality coach like Antonio Conte also needs time and support to be able to build Napoli slowly.
So let's just wait for Antonio Conte to go through that process and fix all the problems that exist and that certainly won't happen this season or in the near future.