I'm looking for specific and non obvious answers. Give me something visceral, rid the world of a figure or nation you hate. Preserve a culture you adore. It doesn't have to make sense either, you are basically god here.
What I mean is don't just say you'd get rid of imperialism or colonialism bc no shit
Personally I would make it so that the Americas are never discovered by the old world and every "would be" conquistador (especially cortez and pizarro) explodes.
I'm showing everyone how to make penicillin and publishing germ theory in the Torah. Kosher practices did wonders for public health, and including modern knowledge of public health will save billions of lives.