“Private” judgement for a RC means they can interpret the Scriptures various ways as long as they do not contradict RC teaching, which they can be seen doing in various ways.
Thus they can both wrest “certain” proof out of Scripture for RC traditions that are not seen officially done, while what constitutes official and even infallible teaching can differ among RCs.
“Thus they can both wrest certain proof out of Scripture for RC traditions that are not seen officially done, while what constitutes official and even infallible teaching can differ among RCs.”
You have fallen into Satan’s trap. He has muddied the waters sufficiently to lead you, and presumably many others, into misunderstanding those things.