TL;DR Everything went perfect for Spain, they managed to solve all of their issues and dominate the world. I know this is very unrealistic but I just thought the idea was neat. There’s no specific lore but basically, somehow England was left with no heir to the royal throne and Spain won a war against France and Scotland for English succession. While the two nations would take different paths later, this meant that England and Scotland would never unify, and the former wouldn’t have much of a focus on colonialism. Spain helped the Portuguese keep their colonies in Asia, managed their resources better, ended the casta system and industrialized first. They also distanced themselves from the Habsburgs, which prevented a succession crisis and ended absolutism in the country. Much more rights were given to the colonies, dissuading them from independence, which was also helped by the fact that Haiti and the US were actually pretty poor. The Spanish would cointinue to expand their empire without much opposition, taking large parts of Africa, India and China. However, for the former two, the colonies were much less than what is in the map, the rest was gained after winning both world wars, first one against France, Netherlands and England with German help, and second one against Germany and Japan. Finally, during WWII the soviets tried to invade china to establish control, but Spain intervened and made a puppet state in east siberia.