Fate vs Free Will

I'm currently reading The Unbearable Lightness of Being and came across an Oedipus reference which tied into our class discussion from yesterday. In this section of the book, Kundera is discussing the main characters interactions at the beginning of their relationship, and reflects on the fact that many ancient myths began with the rescue of an abandoned child. He profoundly states, "If Polybus hadn't taken in the young Oedipus, Sophocles wouldn't have written his most beautiful tragedy!" Though brief, this sentence holds a lot of complexity and can be related to the idea of fate vs free will.
Furthermore, I think by including Sophocles and storytelling Kundera brings another dimension into this concept of interconnectedness. Considering Kundera goes on to liken our lives to a rehearsal in which everything occurs only once, with each action lacking a definitive result, I think it's almost as though he's saying tragedy is necessary for grander stories we may remain unaware of. The tragedy of Oedipus, which has surpassed the limitations of time and confirms the eternizing conceit, wouldn't exist without risk and actions which may lead to destruction but ultimately have additional effects left unknown to those who initiated them.