Roughly speaking, Redaction Theory of the bible holds that one version was given to an earlier group of listeners and then later in the production sequence of copying or editorializing, this message was changed to speak to the issues of the current generation. This concept is wrong because of the repeated and explicit claim that God is intimately concerned and involved in the lives of His people. God knows what the problem is and, despite human creative sinning, the remedy never changes. Redaction theory, at its heart, negates the omniscience of God. Redaction Theory has God changing His mind or worse, the bible is merely the production of humans.

So, how does that square of Roman Catholicism? Roman Catholics believe in the authority of development. They hold to the idea that, over time, the needs of the church changes, and therefore the principles applied to an early group are inadequate to meet the new needs. Catholics believe in a secret oral tradition among the clergy. They will point to 2 Th. 2.15 as their basis for this idea: Therefore, brothers and sisters, stand firm and hold on to the traditions that we taught you, whether by speech or by letter. (NET)

Since Paul is writing to church (see 2 Th. 1.1) he is not only speaking to the clergy. What Paul says is not only his letters are authoritative for the Thessalonians. This does not mean there were secret oral traditions floating about that only the clergy knew about and enforced. Paul had ministered among them and said things the whole church knew about but were not committed to writing. This was merely a way for Paul to avoid pedantically to repeat himself in written form and not to say a secret tradition floats about among the clergy. Further, in 2 Th. 3.6, Paul mentions the tradition he left with the believers (not the clergy) and he defines it in 3.7f. So, in reality, there is no secret tradition.

Yes, The Roman Catholic Church will point to Christ building the church on Peter as another justification of clerical hierarchy but the text doesn’t say what they affirm. I have written about that text here: https://beliefspeak2.net/the-rock/