You have the usual cart in front of the usual horse. As history proves, Tradition came first. New Testament later, and only then by the authority of a council.
Mine is not just my own opinion. It is supported by the vast majority of theologians of history, catholic and orthodox. Yours is born of the faulty assumption that any can interpret scripture how they want, and ( this case) make up any meaning you like for "tradition" , born of current colloquial meaning, not what it meant way back then.
Meanwhile the faith handed down ( i.e. Paradosis, Tradition ) is to be found in the writings of early fathers, as is proven by history , regardless of what you think is " believable" which is irrelevant.
And as a case in point, ignatius to smyrneans proves, most churches are proven heretical right there. Because ignatius and polycarp disciples of John the apostle, stated a eucharist of the real presence only valid if performed by a bishop of true succession. Or his appointee. Nowhere does that contradict scripture - it gives the true meaning to it - but it also proves most denominations and all non denoms believe in falsehood.
And as the divergence of opinion on every single doctrinal issue by reformationists proves, you can't interpret scripture without tradition, because all diverge in doctrine when they do. As Luther said:" it is the greatest scandal" "there are now as many doctrines as heads,"
You still miss the obvious issue. Tradition carries the meaning of scripture. Reformationists tried to separate the two with disastrous results,
Well, it seems to me that that is what you do, not I. However, the other points stand in any case. The verse you cited doesn't tell us what traditions were being referred to and there is no evidence for the vague claim that whatever the church invents was what the Apostles handed down. The most believable concept is that they handed down orally what was to be found, either then or later, in Sacred Scripture.