The responses from Anamnesis are often a high quality.
However I will respond also, having viewed the entire series.
Something you may have caught her mention in the videos is that these motions that you are seeing are grossly exaggerated for the purpose of the viewer and student understanding what is being asked of them, so of course if you try to replicate what you are seeing you may not find it feels completely natural or even within your normal range.
One silly off topic story to add confidence to your initial uncertainty- is there are 2 main ways people hold a pencil when writing, one is the way most are taught, that is to hold the pencil strictly between the thumb and 1st finger with the others curled under for balance.
The 2nd is equally as viable, but with a completely different feel, that is the middle finger replaces the 1st fingers job, and the first finger moves up the pencil for added stability.
Both appear to achieve the same thing, but try them both, one feels completely natural the other feels alien. I, by the way use the 2nd method, however if I had a job in writing and there proved that the 1st method was better, i'd learn it, even if it felt uncomfortable at first.
Anyway back to the point -
The final refined product looks nothing like her initial examples as you see throughout. I think this is worth thinking about that you should not be worrying about the extreme motion, because you are not aiming for that, simply feel what your muscles are doing, get used to activating them, refining them, again look for a teacher before starting this journey, because you'll end up giving up along the way without the proper guidance.