You’re right, it’s not what happened here, because 100,000,000 m^3 is a cute straw man low ball buddy
That rage blast is 3 pixels across the last time it’s visible, shrinking for an additional fraction of a second before contacting with the mountain face about 900 pixels tall in 1080p. The measure isn’t precise, I’m going from memory, someone correct me if I’m wrong. Regardless, even ignoring the additional outside visual acuity shrinking? That’s likely comfortably at least a kilometer tall and it’s dimensions by width are more extreme.
You can scale the blast off Hakoware. I’d bet it’s comfortably at least 3 meters in diameter.
Something like 6 gigatons of a 1 km^3 cube reductive kind of model. That’s ignoring the speed of the vaporized matter ejecting vertically.