Whenever I watch a good piano player, I notice their arms and hands move a lot and it looks very smooth and emotional. Then when I record myself playing, I notice my hands often look stiff and they don't move very much at all. I know playing the piano is about music but when I have an audience, I would like for it to look pretty as well. The sound I produce does often sound very emotional and not "stiff" at all.
I know most movements should be done with the arm instead of the fingers. I often spin my hand to the sides with my forearm muscles to use my thumb and pinkyfinger for example. I try to lift up my forearm more and let it fall down to let gravity do the work, especially when a song gets loud and powerful. Yet my hands still seem so stiff... I make sure my fingering is correct so it's not due to wrong tension in my hands either.
I don't know what else to do, let my hands move even further up? This feels very unnatural...