Before Kandor was enlarged, and nobody could figure out a solution... put the city of Kandor on an uninhabited planet with a yellow sun. All the residents now have super powers equivalent to Superman. They build full sized cities and do whatever else they want to make the planet more friendly to them, and they build full-sized robot bodies for each resident, with a control room in the head of each robot, and then each resident spends most of his life inside his robot body, interacting with all the other full-sized Kandorian cyborgs. When they want to actually socialize in person, they park the body somewhere and exit from the body, joining the other teeny tiny Kandorians in whatever in-person event they choose.

It would be kind of like the society where Shrinking Violet comes from, where they have separate full sized and miniature facilities...