She had mastered several dozens of techniques, techniques Rui had never heard of or seen before. She was constantly using several techniques at once, at a minimum and that number could rise to double digits very often.
Her speed was blurringly fast, and it took Rui everything with the VOID algorithm, Primordial instinct, and the Mindmirror Symbiote to be able to keep up. Had he lacked even a single one of those elements, he would not have been able to keep up with her, even in a passive position.
However, he was no quitter. He racked his brain for a path to victory as he desperately defended and evaded her onslaught. The problem with all-rounders was that they didn't have an obvious weakness. Thus, there wasn't a particularly obvious or straightforward avenue that he could exploit in order to gain an advantage against her.
