For what its worth , I find a way to increase tgp of the nvidia gpu.
After starting nvidia-powerd, it stuck at 80w, but if you cycle throught the performance mode using the fn+q key (its cycle between white/red/blue, which stand for normal/boost/low performance), it go up when using normal or boost and get down to 50w when using low.
Thats very weird because its not consistant, sometimes its 95w, sometimes its 125 , 130 or 140, etc…
But even if the max is set to above 100w, the max used is never more than 100 