"What if"
We're already living in the timeline in which Portugal discovered America.
In the Portuguese speaking world, Cristovão Colombo is not considered that important. It's the Spanish speaking world and, for some reason, the US, which gives him more importance.
It's assumed by many scholars that the Portuguese already knew about America before Colombo's journey.
Yes, let's not forget the Portuguese, one of the smallest kingdoms of Europe, was at one point engaged in what can legitimately be described a World War (3 continents involved) with the Ottomans & their allies.
They were massively stretched through the century
Must have been kind of infuriating to go forth to find new lands and new peoples and keep running into the Ottomans and their lackeys all the damn time. They must have been like Portugal's Klingons.
"Captain, Ottoman ships on sight! Again..."
Sighs "Again with the Ottomans..."
World War indeed, people think multi-continental wars are new, but this one was probably the first legitimate World War.
Yeah the Portuguese were massively stretched at the time, a small kingdom was trying to take over a big chunk of the world's trade and fight some massive opponents at the same time. 16th-17th century, you can practically choose any part of the world map at random and you will probably find the Portuguese there. They don't call them "Heroes of the Sea" for nothing, the Portuguese were doing some insane feats at the time, the kind of thing that would be considered bullshit if you read it in a fictional book - because the difference between reality and fiction, is that fiction has to make sense.
They were at the forefront of naval technology, too. Not just in peace but war - I was reading about portuguese cannons one of those days, their ship cannon design at the time was the best in the planet.
It's a shame the Ottoman-Portuguese War is little known given how much it marked the Indian ocean regions in the 16th century.
Indeed, it's pivotal to world history
Not just India, the Portuguese were fighting the Ottomans and their allies everywhere:
1. In North Africa, where they feared the possibility of North Africa being used as base for an Ottoman Conquista of Iberia, bringing back Muslim domination of the Peninsula. Which might sounds nuts to us today, but that time was the peak of Ottoman Power and the possibility of an Ottoman conquest of Christendom was taken very seriously by the kings of Europe.
2. In Europe. The Portuguese numbered among the allied christian forces in Lepanto, and they also fought another, less know naval battle against the Ottomans, but I can't recall.
3. In Sub-Saharan Africa, where the Portuguese teamed up with the Ethiopians to fight the Ottoman-supported Adal Sultanate. Portugal is practically the reason Muslims never conquered Ethiopia.
4. In India, where the Portuguese also fought for dominance of the Indian Trade against the Ottomans and their allied muslim rulers.