I think it is not too burdensome for Ancelotti because he is used to very stressful work when handling a club. If he succeeds in carrying out an impressive job with the Brazilian national team, I am sure he will be a very successful coach both at the club and in the national team. On the other hand, He will also be back with Vini and rodrygo in the Brazilian national team, i think Ancelotti will get an extraordinary welcome in the first match later.
I doubt Ancelotti will be spectacular in Brazil. The kind of football he plays works well with experienced players who know what they're doing. The current Brazil team don't have good and experienced players who know what they're doing.
I have seen news that he has plans to call back Casemiro to the national team; those are the kind of players he enjoys working with. If Neymar will be able to stay fit, then he's going to be a crucial part of the team like he has always been.
I know how experienced Ancelotti is, but I just don't see him turning this Brazil team around.