“...by itself it is destructive to the untrained.”
No, it says “the untaught and unstable distort” scripture. Of this, there is no doubt. And when they twist scripture for evil, it brings “their own destruction”.
People of evil intentions use scripture to their own destruction, but an untrained person can certainly learn. Scripture doesn’t destroy the unlearned, it teaches them - for “16All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, 17so that the man of God may be thoroughly equipped for every good work.”
Luther, Zwingli, Spurgeon, Calvin, Machen, Smith, et al.
I don’t disagree with you, but if sola scriptura works why don’t ALL of the adherents to it reach the SAME conclusion?