The universe is an endless plane of icy wastes, but some deities placed luminaries in rotation over it which thawed some pieces of land, but they are separated by the wastes and to travel between requires either magic, or treacherous journeys through ice caverns.
check out the Beyond the Ice Wall Worldbuilding Project. the map is great (you can ignore the worldbuilding and just use the map for your own stuff)
i do like that it’s more of a “snowman” and there are other worlds, a large continuous flat plain, and magic grows more intense the more ice walls you breach. it would be great for a steampunk or Weird Victorian setting, or fantasy pirate stuff but could work for modern conspiracy themed world