The part I bolded is the flaw, in my opinion, and not part of the traditional / classical understanding of sola scriptura.Good points. My denomination, Pentecostalism, relies on Sola Scriptura, then, since nothing is given any credence unless it’s explicitly given in the literal sense in Scripture - a position that I find increasingly illogical, ahistorical, and untenable.
From the Lutheran Confessions:
A final norm is not the only norm. It is the norm that norms but is not normed. There are other norms, Tradition.Other writings, however, of ancient or modern teachers, whatever name they bear, must not be regarded as equal to the Holy Scriptures, but all of them together be subjected to them, and should not be received otherwise or further than as witnesses, [which are to show] in what manner after the time of the apostles, and at what places, this [pure] doctrine of the prophets and apostles was preserved.
3] 2. And because directly after the times of the apostles, and even while they were still living, false teachers and heretics arose, and symbols, i. e., brief, succinct [categorical] confessions, were composed against them in the early Church, which were regarded as the unanimous, universal Christian faith and confession of the orthodox and true Church, namely, the Apostles’ Creed, the Nicene Creed, and the Athanasian Creed, we pledge ourselves to them, and hereby reject all heresies and dogmas which, contrary to them, have been introduced into the Church of God.