Can’t make wrist motion work at speed — defaulting to elbow tremolo? (Zenith Passage riff)

Technique Critique
#1

Hi everyone,
I’m stuck on my playing in general. I’ve been working on this riff for ~3 weeks (probably 10+ hours total on this riff alone) and I still can’t play it reliably.

Video: (first take, no warmup)

  1. Problem riff – front view (first take, no warmup):

  2. Problem riff – arm/side view (to show motion/anchor):

  3. Single-string tremolo attempt (no elbow) — this is the wrist motion I’ve been trying to develop for the last months (inspired by Rafael Trujillo’s style), but it feels completely unsuccessful and fatiguing as hell:

  • I can play it clean sometimes, but only after a warmup and with extreme focus / tension.
  • The main issue are all the fast trems and galopps

This is the frustrating part: I’ve been practicing very consistently 6–10 hours per day, and I don’t feel like I’m getting better at technique at all. It feels like I’m just reinforcing the same limitation (and building tension), not improving.

My current picking motion (my best guess)

  • At fast speeds (especially tremolo): I tend to use elbow-driven motion to reach the speed.
    • This gets fatiguing quickly and becomes inaccurate, burns at the side oft he forearm that faces the hand
  • At slower speeds: I use wrist.
  • Over the last months I tried switching to wrist-only, because I feel like a lot of stuff I want to play (outside picking / riffs like this) requires a wrist motion that stays efficient at higher tempos.

Context

I’m taking lessons with Rafael Trujillo and he’s a big inspiration for me, but I still don’t understand how to actually “arrive at” a fast wrist motion if your default is something else.
The motion in this video is basically what I’ve always done, and I feel it’s very limited.

Questions

  1. What does my current motion look like to you?
  2. Do you think switching to a wrist-based motion makes sense for me — or should I develop my current motion instead?
  3. What would be the best test / excercises to find an efficient wrist motion?
  4. Should I post an additional single-string tremolo test clip (max speed bursts) so you can see what happens at higher speed?

Thanks a lot for any feedback.