“She, by an entirely unique privilege, completely overcame sin by her Immaculate Conception”
That statement is one of the reasons I could never ever be a part of the Catholic Church. It flies in the face of Biblical teaching.
You are the first Orthodox with whom I have spoken that is so offended by the doctrine of the immaculate conception. Most simply chalk it up to the difference between the constructs of original sin.
So which EO or OO Church are you a member of?