Infallible Rules of Faith Continued After the Apostles

Protestants believe public revelation ended in the first century, and there are no more living apostles. Nearly all Protestants believe the 27 books of the New Testament are equally inspired. But once again, this infallible truth is not in scripture. So it's an obvious counter example to solo scriptura. If the canon authenticated itself, we'd expect the earliest Christians to describe the New Testament as scripture - but they don't come anywhere close to doing that.