“It is from the teaching of the Church that we know what are the Apostolic Traditions. Church history bears this out. If we were to insist that they be listed in the Bible then they would be Scripture, not Tradition.”
There is no list in existence of the traditions Paul referenced. If there were traditions directly from the Apostles, we’d have a historical record from before 100ad. We simply do not.
Nor do we have an historical record from before A.D. 100 of what was considered Scripture. By your own standard we should not be able to know what is the Bible. Nor do we have any evidence that the early Christians held to Protestant beliefs. But we can see what the early church taught and practiced as handed down from the Apostles. The early Church was just as careful in preserving Apostolic Traditions as they were in preserving the Bible. Read the Church Fathers.