You really do have my sincerest sympathies. You see I understand your position is completely untennable, even if you don't.
Acknowledging the Spirit's inspiration of human authors says absolutely nothing about the content of the revelation, and the fact is there is no revelation in the Scripture authorizing sola scriptura.
Or do you believe as some that God cannot successfully communicate His word by His Spirit through human authorship?
So why is it so preposterous that God can successfully communicate through the human agency of the Church?
You can't have yours without giving me mine.
You, and a few others may have misunderstood my intent. By saying, “There is no going outside of Scripture when God, by His Spirit, inspires the human authors of His Scripture to pen His word,” I am simply stating that it is then that those writers cease to become conduits of their own thoughts and are now indicating the thoughts of God. The scripture verses I cited were to indicate that this is what God does. He communicates His thoughts. He has used human instruments to do so.
When you speak of an institution acting in this same capacity, I would say, “With God, all things are possible.” But, that would not be enough to “give you yours.” That institution’s members would have to be operating in such a way as to be fully inspired by the Holy Spirit of God and acting in one voice in such a way as to be of one mind in matters concerning God’s revelation of Himself. They would, likewise, have to be completely consistent with God’s character, nature, person, work, as well as completely in line with every jot and tittle of His previously revealed word.