I fully agree with you, he is one of the most complete and successful coaches of all time, he is truly the number one capable of creating a cohesive group of players like Real Madrid, all young and so successful, to think that when he was at Napoli he was criticized, I am truly shameful and he was right to leave
Ancelotti is known as a coach who has no tactics but he has always been successful at any club. I think no other coach can match his success and in the modern era of football it is very difficult to find a coach like him. Pep Guardiola as one of the coaches with the best abilities has not been able to match what Ancelotti has achieved, let alone if we talk about the current coaches whose abilities are still below him.
Next season will be a step for how Ancelotti can defend the Champions League title and now the support of the players he has is very supportive. Mbappe is expected to be one of the players who can help Real Madrid defend the Champions League title next season.
Now Ancelotti even leads as the coach with the most Champions League titles, it proves that he is indeed a very good coach as proven by his success in the Champions League. Even though many say he is poor in strategy, this is not supported by the statistics he has recorded. The achievements he can achieve say that he is a good coach. Indeed, in the game he doesn't apply many complicated strategies like controlling the ball a lot or things like that. However, when attacking, he can make his attackers very effective in taking advantage of opportunities to score goals.
The way he prepares the team for the long term is also very good, we can see that at Real Madrid. Some of the players he managed to bring in were young and could perform well, so that was a big asset for the team he was managing for the future. Even though he won't be at Real Madrid forever, he left something behind that makes Real Madrid ready for the future.