Atlas something i can work on
Good, we need another Sun and Another Planet, Our sun remains only 5 billion years and Earth got around 1.2 billion years of Geological activity (according the scientist)
Change to
K-type main-sequence star they got lifetime 15 to 30 billion years, compared to 10 billion for the Sun
Such a star is
Epsilon Indi https://en.wikipedia.org/wiki/Epsilon_Indi or
Epsilon Eridani https://en.wikipedia.org/wiki/Epsilon_Eridani
On Planet take a Super-earth
https://en.wikipedia.org/wiki/Super-Earth
More mass means longer Geological activity as Earth has and with large Diameter the planet got earth like Gravity and bonus:
Distance between the distinct "civilizations" best by large ocean or extrem vast Dessert or active Vulcans zone.