Yes, that’s the origin of the name. It comes from the influence of Ethiopian Tewahedo Orthodox Church, a sister of Egypt’s Coptic Church. But it’s a cultural relic that no more denotes personal Christian faith than possession of the family name: Christian, Christianson, Christensen, etc.
The “advanced” teachings of Jesus are contained in the preaching of the Apostles and other earlier followers. It’s called: The Gospel.
No one is interested in rehashing second century doctrinal controversies with you. Take a course in Christian Origins and read Irenaeus and cure your own errors. You might also consider the history of Christianity in the Middle East-if you think faith survived 2000 years as an “institution” there, you have a big surprise in store.