It's really interesting to think about the accents in Brazil. I was born in Minas Gerais and raised in Brasilia, and throughout my entire life, I have noticed differences between the way my cousins speak among themselves and the way I speak to my sister. It sounds like they are singing when they are speaking. It's very funny and I like it.
Every time I watch videos about different accents in a different country, for each region they show either an actor or a TV host with the accent from that region. In Brazil, this would be impossible, because everybody on TV speaks with kind of the same standard Portuguese accent, which is exactly the way I speak.
As I grew up in Brasilia, I always had friends whose parents came from many different places in Brazil, speaking with very different accents. People from the south speak with a very emphasized 'e' sound at the end of words like 'leite' or 'quente', meanwhile people from the northeast speak with a strong 't' and 'd' sound in words like 'tiara' or 'dinossauro', and people from São Paulo roll their 'r' sounds. People from Rio often pronounce 's' like 'sh', etc. But one thing all of the parents who move to Brasilia have in common is that all of their children speak with the exact same accent as people on TV.
So, in Brazil it doesn't matter if you are from a rich family or a poor family, your accent is defined exclusively from the region you were born and raised. What changes from one person to another is the level of formality, slang, and speed of speech.