The great problem with placing a (Catholic) magisterium on equal footing with Scripture is that one must overlook the great pile of excrement it stands on. Manifest herocies such as the cult of the virgin and apostolic succession to name two. The only thing that made Rome the head of the Church was Rome. In the end,”Because we say so” is their final answer.
Catholics, on the other hand, recognize that the true “rule of faith”—as expressed in the Bible itself—is Scripture plus apostolic tradition, as manifested in the living teaching authority of the Catholic Church, to which were entrusted the oral teachings of Jesus and the apostles, along with the authority to interpret Scripture correctly.
Meaning distinctive Catholic teachings are not manifest in the only wholly inspired substantive authoritative record of what the NT church believed (which is Scripture, especially Acts thru Revelation. and which best shows how the NT church understood the OT and gospels).