Apparently there are no recordings anywhere that the prophet (pbuh) prayed 20 rakah taraweeh. That the prophet (pbuh) only ever prayed 8 rakah taraweeh is the only count recorded. I understand that Umar (may allah be pleased with him) introduced 20 rakah taraweeh after the prophet? Why? Was the islam taught by the prophet not perfect? Did Umar know islam better than the prophet?
I understand that the prophet thought highly of Umar:
"If there were a prophet after me, it would have been Umar" Sunan Tirmidhi, Volume 2 page 754.
But it says if
he was a prophet, so he clearly was not a prophet, so are non prophet (but highly pious) people allowed to make alterations to the original islam taught to us by the prophet?