As a video editor and VFX expert of 50 years, I studied this video frame by frame and I stake my professional career on this... this video is unedited and she appears to really move that fast. Based on the amount of frames in the transition from Pose A to Pose B, cross referencing with the bpm of the song as well as the frame rate of the video, and feeding the data to a special algorithm, she moved close, but not quite, to the speed of sound.
vtubers if you spent this much on your model PLEASE look into how to set up the tracking
it takes like 2 seconds and it’s so obvious when people don’t do it