I speak Portuguese and English. Should I learn another language?

I don't know where you are in Brazil. There are many languages spoken there, Giselle Bundchen's family speak the Brazillian variety of German, Hunsrückisch.

Brazil is surrounded by many Spanish-speaking countries and Paraguay has Guarani. Of course, you have to cross the waterfall to get there.

Having people to talk with is important, , but picking a language with good literature and opportunity for work and travel may be more important. I think learning Spanish will answer many of ordinary requirements, but French and Dutch would be useful with Brazil's neighbors also. Spanish is also the second language in the US. Only Mexico has more speakers than the US. The US passed Spain just this year, and the number is growing.

Think about your interests and ask language teachers about how well their specific language might fit you. If you are a rocket scientist, I'd learn French and go to French Guiana.

https://en.wikipedia.org/wiki/Guiana_Space_Centre

I live in central California. We have large Spanish and Portuguese communities. The Portuguese came here many years ago from the Azores, so they speak a third variety of the language. Our little city of Arroyo Grande just had a Portuguese festival.