Doctrine in the Catholic Church rests on the Magiosteirum's interpretation of existing official scirpture and historical teachings of the Church. Doctrine among Protestants is up to an individual based on extant copies of the Bible.
Be it as it may, doctrinal among all Christians at the present time is over the interpretation of extant verison of the scirptures.
This was not the case in the first 300 years of Christendom, when there were many variant verison floating around. There is biblical evidence that many passages were redacted to reflect doctrine or to bring it into ahmrony with the current doctrine. We know about some of these through references made by others repeatedly, or by actually having variant copies at hand.
All doctrinal differences result from either (1) variant biblical text or (2) variant interpretation of biblical text. Since all biblical text was aritifically made to agree with the earliest condices known, because they agree wiht the verison of the Bible accepted by the Church. Competing verison were either destroyed or buried.
So it is no wonder that all our copies of the Bible closely agree; it's artifical agreement! It does not prove that this is as close as it gets ot the original or that God preserved his scriptures from corruption.
From extant copies of variants we can see apt tern applied by Church scribes in trying to diminish or eliminate various divergent doctirnes based on variant copies of the Gospels and other NT books. Specifically, older versions of the NT were changed to reflect Church doctrine more closely. This was accomplished by chaing verses that sounded docetist, Gnostic, separationist, adoptionists, etc., and replacing them with vereses that sounded more "orthodox."
I seriously don't understand what you are disputing here except the banal position that changes in scriptures have no effect on doctrine.
“From extant copies of variants we can see apt tern applied by Church scribes in trying to diminish or eliminate various divergent doctirnes based on variant copies of the Gospels and other NT books. Specifically, older versions of the NT were changed to reflect Church doctrine more closely.”
The experts I’ve read disagree with you. Folks working on the text are trying to get it as close as possible to the original, not trying to make changes to create false harmony.
Changes come with time...older versions are not the changed ones!