I’d ensure Spartacus’s slave revolt succeeded, resulting in Rome falling to a grand slave revolt, smothering in the cradle the pro-debtor/creditor government and empire. Probably just delay it emerging later down the line but who knows. But best part is this stops a lot of follow-on bad happenings such as Christianity being proclaimed the official religion of Rome, certain unifications don’t occur under wartime conditions against Rome. Maybe they even implement a kind of early universal suffrage and it ends up failing but it means that 17th century enlightenment thinkers have more to chew on which means they and the French revolution see certain flaws in liberal thinking and advocate a more radical course of action leading to the US founding fathers being a bunch of, republican, class traitors and hardcore abolitionists which leads to a crumbling of the capitalist world order over time that means the German revolution succeeds and European capital is murdered off in a bloody series of revolutions ending by the year 1980. While simultaneously anti-colonial sentiment creates uprisings across the globe that further weaken capital. Thus global communism by 2040.

(Yes I know there are problems with this but let me dream)