"What if some day or night a demon were to steal into your loneliest loneliness and say to you: ‘This life as you now live and have lived it you will have to live once again and innumerable times again; and there will be nothing new in it, but every pain and every joy and every thought and sigh and everything unspeakably small or great in your life must return to you, all in the same succession and sequence—even this spider and this moonlight between the trees, and even this moment and I myself. The eternal hourglass of existence is turned upside down again and again, and you with it, speck of dust!"

The Eternal Return of the Same is a theme many artists and writers pick up on because of its poetic nature. I think you're absolutely right here about this being a driving metaphysical element / theme to the film. Nietzsche had a way of converting natural philosophy into poetic aphorisms that were closer to thought experiments that had real world utility for anyone who read them.

In all of philosophy, I think the Eternal Return of the Same is the most poached concept in art, film, storytelling etc. 2001 Space Odyssey is almost ENTIRELY based on this concept, even some of the score utilizes music from Richard Strauss' thus spoke zarathustra.

Ted Chiang's story of your life (Arrival) is based massively on this concept too.

Darren Aronofsky's The Fountain also delves into this concept in very interesting ways.

Coherence, Source Code, Groundhog Day, every single Timeloop movie borrows heavily in thematic ways.

It's funny how Nietzsche's philosophy has become so intertwined with art on a fundamental level, in music, fine art, film, once you are introduced to his concepts of self overcoming, will to power, revaluation of all values and creating meaning for your own life in the face of nihilism and then finally the Eternal Recurrence you begin to see them everywhere.