(For your purposes, avoid Chilean Spanish too.)

Spanish classes in the US vary a lot. You don't want to learn/speak European or Argentinian Spanish. I'd say the "blackest" Spanish is Caribbean Spanish, but this is also relative, as just like in Portuguese, there's not a clear Black/Brown Spanish (maybe there is, but also spoken by white people).

That said, there are definitely popular, or even "hood" Portuguese variants in Brazil, that are more Black/Brown, although white/light-skinned people who live in the areas where these variants are spoken also speak it. But the bottom line is there's no clear color line in the Br Portuguese variants

Most Portuguese classes in the US teach Brazilian Portuguese, which is not colonizer Portuguese, but it's not Black/Brown Portuguese either, in part bcause there's not a purely distinguished Black/Brown variant in Brazil like AAVE. Differences are mostly of class-region, more than race-culture.

“Afro-Brazilian” here. I have been thinking about the same for some time without ever finding a clear answer. I like the inversion of terms proposed by some: American-African, Brazilian-African. Not sure if folks in the continent would agree though, but not sure if they have a say on that either.