You may want to look into the genetic composition of modern-day Brazilians to consider whether "Amerindians were exterminated" is a coherent way to represent it.

edit: we are just comparing 2 completely different models here. You're not wrong about some things, you are just talking about a different thing than I :)

edit 2: you are lacking information if you think that Brazilian Amerindians did not also partner with European powers (France and the NL itself comes to mind) against the Portuguese and it's somewhat amusing that you think that Portugal was never challenged on that vast territory by other powers.

My point still stands. Their culture was completely decimated and they were largely replaced by European and African migrants, indentured servants, and slaves.

Subjugating a native people that lacked metalworking, gunpowder, and literacy is different from conquering multiple nations that had all of those and was backed by the Ottomans, Mughals, and Americans.