Excellent ideas!
Lurkin, an underground antarctic “colony” would be a great project for a religious group in the USA looking for a place for religious freedom.
Think “Techno-pilgrims”
Powered by either geothermal or Molten Salt reactor, farming underground using vertical farming, export industry based of semi-conductors(to get things that are unattainable underground).
Need to expand for population growth? Dig more tunnels and setup more “hubs” underground, plenty of space to expand 3-D under Antarctica, (most of Antarctica is over 4,000 ft above sealevel). Settlements would be “branching hub” architecture spaced out enough to allow for plenty of growth. The average underground temps would be between 40-60 degrees F even in Antarctica. You could make nice “open spaces” in the center hub like areas like parks with artificial lights and Day/Night cycles. etc...
You could settle a billion people in an area the size of the state of Connecticut.