lol, the trans-pacific route was pointless. Portugal monopolized the Indian ocean and spice trade for more than 100 years. It established the atlantic triangle trade of Africa (supplying slaves) to Brasil (supplying sugar) to Europe. All of them comercially viable for centuries. Meanwhile, Spain could barely cross the Pacific ocean and make it the viable trade route to the spice islands that it longed for to be.
Many forget that the circumnavigation of Magellan was both a mistake and a failure. The discovered pass to the Pacific, the southernmost point in the planet not counting Antarctica, was considered unnavigable most of the year (the magellan fleet had to wait 6 months at Puerto San Julian before daring to continue the search, surviving its first mutiny attempt), before treading the slow currents of the Pacific, which took down the majority of the fleet to scurvy (while most likely contributing to the madness of Magellan, which made him the delirious zealot which jumped foolishly to his death at the hands of Lapu Lapu). In fact, part of the fleet tried to make it back through the Pacific, only to give up again, come back to the spice islands and be captured by the portuguese, while the remainder barely made it back, commanded by Elcano, one of the mutineers of Puerto San Julian; a route that btw, they feared taking, as it was in direct violation of the Tordesillas treaty and would certainly condemn them to death would they be discovered. 1 ship out of 5 made it back. 18 out of 270 men. By the time they arrived, the new world colonization was still mostly considered a failure, Columbus still an outcast, not even worthy of naming the continent he discovered (this was roughly 18 years before the Aztecs, Incas, and all the gold and silver that got plundered).
Meanwhile, the portuguese routes remained largely uncontested, that is, until a certain young portuguese king died in a battle in the north of Africa leaving no children, thereby opening the door for the two crowns being ruled by the same king, and with it, making Portugal a target for the many enemies Spain had been collecting along the way. And that was the beginning of the end for the portuguese century.
The Manila galeon is certainly an historic milestone, but it connected America with Asia. Payload needed to be carried by land all the way to the Gulf of Mexico before departing to Europe. Barely global, if that's what's implied. It started quite late in the history of the spanish in Americas, some 100 years after the conquest of Mexico, because until then, extracting and transporting all the gold and silver to Europe was considered more profitable, until there was so much silver in circulation in Europe that it devalued it, thereby making Asia a more enticing market for its silver, as it was still considered valuable by then. The route also lasted a bit more than 50 years. Consider that the portuguese route to India was still being navigated way into the end of the 1800s, and only being truly disrupted by the opening of the Suez canal.
I'm not here to downplay the several achievements, or exacerbate the atrocities of the spanish empire. Every empire had them, no less the portuguese (while they did not come up with the idea of slavery, the atlantic triangle is responsible for the biggest intercontinental forced transfer of human beings in history, and the massive economic dependence it created in African kingdoms caused its brutal collapse after the abolition). But not calling it the first global empire of the discovery age, specially taking into consideration that they literally started a century before anyone else, is factually incorrect.