Argentina dwarfs Brazil: about 2,782,703 km² km² against 8,499,400 km² km². At true size Argentina is about 3.1× larger — the whole of Brazil fits into Argentina roughly 3 times.
Both sit in South America, so this is a same-region comparison: the new Equal Earth map draws both with the same honest geometry, and the real gap is exactly the 3.1× you see above.
The old map muddied it further: Mercator inflates Argentina about 1.5× and Brazil about 1×, so on a Mercator-style map this pair appears 2.1× apart instead of the true 3.1×.
Argentina fits 3× into Brazil.