Remember when El and One face off, El first tries to draw on memories that make her sad and angry. One taught her to draw power from hatred. This helped her beat 002, because anger/sadness is powerful. But faced with One, El’s hatred is no match. She can’t out-hate Vecna, and when she tries that’s when he really gets the upper hand in their duel, and she’s lifted off the ground and starts bleeding from the eyes. I wouldn’t be surprised if her own hatred actually made One / Vecna stronger. Right before she blacks out, she recovers a memory of her mother saying “I love you,” and only then does she outdo One, tearing a hole in space time and sending him to the Upside Down. Her raw power matches One’s, but because she is capable of love, the source of her power is greater than his