Hegemons can't integrate their Hegemony subjects though. So you can't really count it as "your" worlds. You could start integrating a starting vassal on day 1 and finish integration after a few years.Hegemons give you three homeworlds as does voidborn. One vassal, potentially with fewer starting pops would not be overpowered or even the strongest of the current origins.
And Voidborne is a different matter altogether. They have their own downsides in return for starting with 3 "worlds". Also they don't start with more pops.
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