Nietzsche's eternal return is a view that there are certain inevitable highs and lows in life that happen no matter how many times life is lived.
As Emrys Westacott writes, the "heavy responsibility "(?) is to take a positive attitude to this predicament.
the ultimate expression of a life-affirming attitude: to want this
life, with all its pain and ...
I'm (more than) a bit of a Nietzsche buff. I have thoroughly read everything Nietzsche wrote as well having read much of what most reputable Nietzschean scholars have written. The closest I can recall him coming to saying something like this is, "We have art lest we perish of the truth."