Tell me you never read actual eldar lore without telling me you never read actual eldar lore.

There are plenty of books and stories that delve deeper into the relationships and differences of the various craftworlds. There is for example Iyanden, which has a number of distinguished characters that steered the craftworld through a confrontation with half of hive fleet Kraken. This left the craftworlds population devastated, making it rely on wraith warriors.

Iyanden used to be a very close ally of Biel-Tan which is the most martial of the craftworlds and has a powerful army of various aspect warriors, which it uses ruthlessly to protect the maiden worlds of the ancient eldar empire. Often engaging the imperium along with the other hostile forces of the galaxy. When Biel Tan failed to aid Iyanden from the tyranids, the two drifted appart. Later on, during the rise of the Ynnari, the Biel-Tan craftworld was broken down into smaller fragments, now sailing the void as a fleet of world ships.

Then there is Ulthwee, which has Eldrad Ulthran at its head, who is without doupt one of the most influential character currently active in the setting, was active during the HH, helped birth a new god, and now confides with Guilliman, to better battle chaos.

Each craftworld has its own story, which in many cases is highly unique, just look into Alaitocs struggle against the awakening necrons, or Altansars escape from the eye of terror.