How the Catholic Church defines heresy is how the Catholic Church defines heresy and does not apply to God's truth. How does the Catholic Church define "apostasy"?
Why is it when Catholics cannot address a single issue they bring up the non-existant apostolic succession of unproven traditions?
Study the history of the Hebrews and you will find God kept a few from heresy and apostasy. The few were not limited to the Levites (God's priests). In fact at the time of Jesus the Pharisees had "seated themselves" on the chair of Moses. The Pharisses had usurped the authority of the priesthood and were teaching "traditions" not God's truth.
How does Paul describe himself?
Galatians 1:13-17
13 For you have heard of my former manner of life in Judaism, how I used to persecute the church of God beyond measure, and tried to destroy it; 14 and I was advancing in Judaism beyond many of my contemporaries among my countrymen, being more extremely zealous for my ancestral traditions. 15 But when He who had set me apart, even from my mother's womb, and called me through His grace, was pleased 16 to reveal His Son in me, that I might preach Him among the Gentiles, I did not immediately consult with flesh and blood, 17 nor did I go up to Jerusalem to those who were apostles before me; but I went away to Arabia, and returned once more to Damascus. NAS
Paul did not receive his teachings or his authority from Peter or any other apostle; he received both directly from Jesus Christ.
There is also a 5th view of the 7 churches of Revelation. They were historical and contain teachings relevant to all churches throughout the age and demonstate that there are such churches throughout the history of Christianity.