I think the definition of the Star Wars saga depends on which trilogies you include.

If you only include the OT, it’s the story of Luke Skywalker. We watch as he goes though the hero’s journey, in the style of classic mythology.

If you add the prequels, it becomes the story of Anakin Skywalker. We watch as he rises, falls, and rises again, in the style of a classic tragedy.

If you add the sequels, it becomes the story of the Skywalker family. We watch as they go through their lives, ending with someone who isn’t part of the family taking their name.