I think your problem isnt a matter of see or dont see youtube performings. It seems as you feel tired after play a lot of times the same composition. With the repetitions, the composition becomes repetitious because it loses novelty and risks to become fastidious. I believe it`s a risk for all us. As human beings, we aspire after the infinite, we are never satisfied with what we have already, isnt true? So, with a musical piece, when you have it "in your fingers", it turns to you a sequence of notes and sounds, as if it losed its beauty...
Perhaps you may try "mental playing", earing in your mind the piece you are learning, looking for the intrinsic beauty of each musical phrase, singing it inclusively (remember Glenn Gould...). Then you may return to the keyboard and try to reproduce exactly what you ear in your mind.
It`s very important to record your playing.
As all in our life, music is also 90% of perspiration and only 10% of inspiration, you know?
Best wishes
rui