What? You can parry Shichimen violet balls? Now I feel stupid for trying to run past them and rushing the boss, while using some consumable.
You can parry them. In theory. I'd still go with your current approach, though.
Thing is, this Ongbal dude that uploaded the video, he is, as the kids nowadays say, "built different". Even after watching his videos and studying the patterns for these uncommon parries from him, I was able to replicate them maybe 1 time out of 10. Maybe it's just because my reflexes are shit, but if you watch some of his other videos, you'll see how much that motherfucker mastered the parry game to a level us mere mortals can't hope to achieve.
I mean, the crazy fucking bastard plays Elden Ring like a parry-based game, ffs.