I think you might be able to draw a parallel with long-running serials like comic books, or even Star Trek itself. They tend to revisit old themes and revolve around a certain status quo.

They tend not to involve multigenerational obedience to an authoritarian regime, though…

The First Fifteen Lives of Harry August. It tells the story of a man who lives his life over and over again. Very interesting story and while not exactly like Garak’s repetitive epic its definitely in the same vein.

I feel like repetitive epic is like a Cardassian version of the dubious literary idea of The Hero’s Journey, adapted for the Cardassian heroic ideal of selfless sacrifice to the state. I think Garak would appreciate the “Rememberence of Earth’s Past” series (Three Body Problem) for the way that individual heroics take a backseat to the glory and survival of the state.

I love this question. My first thought was not a book, but Béla Tarr’s The Turin Horse which depicts the repetitive life of a Hungarian farmer and his daughter. Each day is essentially the same, with similar but ever-changing frustrations, and no hope for change in sight. The audience really feels their frustrations, but the characters also appear to have fully accepted the situation. The title is a reference to the horse-whipping that allegedly drove Nietzsche insane.

Not quite an “epic” in the usual sense, but absolutely repetitive and a surrender to economic powers beyond one’s control.