Peter called Paul’s writings scripture.
When?
I just recently learned this myself, but Peter does mention Paul’s epistles in 2 Peter 3:15-16:
And account that the longsuffering of our Lord is salvation; even as our beloved brother Paul also according to the wisdom given unto him hath written unto you;
As also in all his epistles, speaking in them of these things; in which are some things hard to be understood, which they that are unlearned and unstable wrest, as they do also the other scriptures, unto their own destruction.
At the time, they were still in the midst of writing stuff. How can there be sola scriptura when everything written was new? This scripture they were writing was the “new tradition.” There was no precedent. Now it’s old, but then it wasn’t. They were breaking tradition, saying unclean food was okay to eat, that circumcision wasn’t necessary. If the church fathers were the Apostles, there was no sola scripture because it was still in the process of being written. If the Church fathers were the ones deciding what would be included in the New Testament, after all the original Apostles were gone, that’s a different question. Who, in the original question, are the church fathers?