“And Scripture doesn’t say that every religious truth is contained in Scripture, or that Scripture the sole rule of faith”
I don’t know a single person who believes either of those items. Perhaps you do?
First, God has revealed authoritatively what He wants us to know.
Second, that revelation is His Holy Word, which is the ultimate or final source of knowing truth. Every teaching is to be judged by what He said. Every tradition is to be judged by what He laid out. Every doctrine is to be grounded in what He revealed.
best.
It's just another Catholic talking point that is mindlessly repeated whenever a Catholic wants to justify the church ignoring Scripture and adding tradition.
There's no interest in learning the truth because they've been told it often enough and yet still persist in mindlessly repeating their Catholic talking points.