Some of Brazil players have been coached by Ancelotti and they're doing pretty good. Vini and Rodrygo is in Madrid and Ancelotti has been able to manage them and build them. Brazil National team has suffered a lot of humiliations from other National teams, I think that it's high time for Ancelotti bring them back to the light.
Brazil has experienced a decline in overall team performance making it difficult for them to compete with other national teams in several official competitions. Ancelloti's presence is expected to bring big changes to the national team and they can return to the peak of glory that has been lost for a long time. Some Brazilian players are close to Ancelloti's training style so it will be a little easier to adapt and Ancelloti himself will also be a little easier to adapt because he knows some of the national team players.
Ancelotti emotional closeness with several Brazilian players will certainly speed up his adaptation period, I don't think Ancelotti will experience any significant difficulties. The World Cup qualifying round will be a good event to build chemistry, we will see clearly how Ancelotti performs at the national team level. I think all managers will still need time to improve the team performance, especially to bring Brazil back to its glory days. But at a glance, I think Ancelotti has the ability to do it, he is in the right place and the right time.