"Structural damage" in my world is casing cord damage. But without a hands on or Xray vision look at all I'll say is that there's some slight bulging around the base of the plug that could be from the tread cap's "rubber" being forced away from the hole by the plug. What air pressure is in the plugged tire?

Tire blow outs from casing cord damage is usually from the tube poking out the casing and sort of "aneurism/hernia" exploding. Tire casing cords don't generally continue to tear after the offending object is removed. So for tubeless tires I wouldn't expect the cords to further break, causing the hole to expand.

But the proof is in the using. Try riding it. If you are uncomfortable in doing that then just replace the tire and ride with peace of mind again. Andy.