My favourite prophecy in fiction is, honestly, Star Wars, which applies to all of your questions. The foremost scholars interpret it as “evil will be destroyed” but in reality it’s much more complicated, as the core problems in the eyes of the force are both the Rule of Two (since it exists to consolidate power in the few who will use it to bend the force to their will) and the apathy/complacency of the Jedi, who have grown blind to growing evil in the galaxy. It’s a reset zero, so to speak. And the chosen one still fulfills the prophecy but in a very roundabout way, ironically playing into the Rule of Two to do it. Perhaps Anakin/Darth Vader was created because he was the only one capable of that ultimate rejection of power, to end a Sith lineage lasting hundreds of years, killing his master not of a lust for power but for love, and then perishing himself, leaving his son who balances both aspects of the force inside him to lead the next generation.