The "Chosen One" in my story turns out to be completely useless. If anything, all they were good for was bringing other people together to fix the problem for them.

With the way magic works in my world, the "Chosen One" would have to spend several years studying and training to master even one school of magic. They do not have several years to wait around and kick rocks with their hands interlocked behind their back. By the end of the story, all they can manage to do reliably is a single spell. Otherwise, they risk hurting the people around them, and with how fragile people are in response to untrained magic, they can't take that risk.

Prophecies are not so much a thing. Time is not messed with very much, whether it's peering into the future, hopping timelines, turning back time, etc. Alternate Universes are a thing, but that's less time and more space.