It’s important to remember that Rey is part of the prophecy.
Darkness rises, and light to meet it.
This implies a nobody had to rise to counter Kylo, which is frankly ridiculous but if we are working the lenses of TLJ, Rey is both a “nobody” and a “chosen one”.
That wasn’t a prophecy, it was just something Snoke said. He also lied about creating the Force dyad, so we can assume he isn’t the most reliable narrator. But you are right that it’s ridiculous.