The Portuguese obviously discovered Brazil before Columbus (or worst case, contemporaneous), because of the dividing line drawn up in the Treaty of Tordesillas:
https://en.wikipedia.org/wiki/Treaty_of_Tordesillas
It's not known how they did so (windblown fisherman, or expeditions that kept knowledge secret, probably both). The truth is that the passage from Europe to Cape of Good Hope - and back - is much more natural following trade winds via Brazil.
I am always skeptical of these people who row from Spain/Azores to the Caribbean or mainland S. America, because if you push a boat out from the Azores at the right time of year, that's exactly where you will go. If I look at the speed of the 'rowers', compared to the sea drift of a small boat, I find they reduced their time by 50-60%.
If someone puts up a small unattended sail, or even had a bigger wind cross-section of a larger boat (with unused oars :), they would beat the rower every time. There are several records of unmanned boats abandoned in storms, or torn lose from their anchors, which float the crossing in similar times. The rower only wins in calm seas. The exertion of the rower may be admirable, but the time and the crossing are not.
Coming back is similar, but more demanding. First, you have to go north to find the westerly trades and the Gulf Stream, but once you do, your passage will be swift. However, the seas of N. Atlantic are stormier and colder, so if anything goes wrong, you are in a lot more trouble.