The “fuzz” is likely to be the result of camera shake from the natural daylight component of the
exposure, whereas the flash component (having a much shorter duration/
exposure) will contribute to the sharper details.
Hand holding at 1/128 with one hand on camera whilst holding the flash in the other is the likely culprit in causing the camera shake.
When I use flash in macro photography, I’m usually shooting at 1/250 at F11 which in most instances, “kills” the daylight component leaving just the flash as the main
light.
Cheers
Dennis