Sigh.
The Church has authority to discipline members. That covers the two passages you mention. Totally agree and have taken part in it in churches.
Instead of looking at the “disunity brought by private interpretation”, look at the heresy brought about by the political rulers of the Roman Catholic Church, to include replacing the Word of God with their man-made rules - from “priests” to “Purgatory”.
We need a standard and that standard is the Word of God. Not the Roman Catholic Bishops and Pope, most of whom have been non-Christians.
The churches ACCEPTED the New Testament but did not create it. NO church or Bishop directed its writing. The churches role - and not just the ROMAN church - was to reject phony additional scriptures - and the Roman Catholic Church failed to do that in spite of Jerome’s urging.
“If you think Christianity will flourish in the world without the Catholic Church, you haven’t been paying attention”
If you think the Catholic Church is seriously “Christian”, you haven’t been paying attention!
A Church that only has the authority to discipline its members is no Church... it's a prison. Go back to 1 Tim 3:15 But if I should be delayed, you should know how to behave in the household of God, which is the church of the living God, the pillar and foundation of truth. It is not just a Church of discipline but of truth. She has shared this truth since Her foundation by Christ Himself.
A Church that requires the private interpretation of Scripture is both anti-Scripture (2 Peter 1:20) and ahistorical. From the time of the Gospels until Gutenberg's printing press, it was impossible that people received the Good News from any source except the Church. Bibles were printed by hand and were not obtainable by any other than churches for use in liturgy or by the very wealthy who could commission their own copies.
The churches ACCEPTED the New Testament but did not create it.
A laughable assertion! Who wrote the New Testament? The Apostles. What were they doing at the Council of Jerusalem (Acts 15) if not governing the Church and expounding on the Gospel? They decided that Gentiles didn't have to become Jews like them in order to be part of the Church. It was their decision to make and made from their authority to govern the Church given by Christ.
If the Church requires each to read the Bible for His own salvation, there was no Church until Gutenberg made it possible. That negates 75% of Church history... and makes no sense whatsoever.