To win big titles like World Cup or Euro, you will need a strong and balanced team, and you don't need one or two super star players in your team while other players are under quality. This will make an unbalanced team that are not quality enough to win World Cup or Euro title. Brazil in recent years still have some super star players but their squad is very unbalanced that reflected to their bad performances in both World Cup and Coppa America tournaments.
We have players like Vinicius Junior, Rodrygo, Raphinha, Marquinhos, Gabriel Magalhães, Alisson, Ederson, and Neymar, but we were unable to win big matches. That is too disappointing. Don't you think these players have the capabilities to play better football? Neymar is always fighting against Injury. Sometimes he gets unavailable for big matches. But we have quality players who have the capabilities to win against any team on their good day.
Argentina recent years have better squad with balance between attacking and defense systems, and there are players who can support Messi, cover his lack of proactive defense, and maximize contributions and effects from Messi. As a team, they are united, strong and ambitious together with enough luckiness, they have won some titles recent years.
Their luck has been with them in the last few years. It's not like Brazil does not have quality players. I think their goalkeeper, Emiliano Martínez, helped them to win the World Cup and the Copa America as well.