This is the fbx you’ve provided.
lol, i meant 1 key per channel per frame 
Otherwise it won’t move a lot, maybe 1 tip of a finger 
But it’s i guess that Armature Mixamo is not that bad if the mesh is reduce to 6K vertexes, rebake the animation to 1key each 3 frame and remove the location and scale channels. But still, the other armatures perform better with same number of bones and keyframes
I was misguided per some strange behaviors of the armature sometimes. Bahh, i jumped in the BGE very quickly .
Thx to all