As to your question of who determines (or did) the canonicity of scripture.
(in other words your assertions we must depend on maybe the catholic church or some human agent for the bible to be transmitted to us)
My answer is that God himself will arrange the circumstances to insure we get the canon.
Tradition is NOT the bible.
I believe God had a hand in the events that led to
1) The recording
2) the preservations
and
3) The construction of what we consider the scripture.
God does not NEED man, nor any agency (espeically tradition) to achieve his means.
Also, do not forget our first revelation - that is, general revelation (Romans 1:20). Which, agrees of course with specific (special) revelation, that is, the scriptures.
Tradition is not to be trusted. It’s not a construct of God.
Mark 7:8 You have let go of the commands of God and are holding on to the traditions of men.”
i completely agree God will be sure we get the correct canon.
why do you believe God allowed the wrong canon to be adopted for the first 1,500 years of the Church and He took until the 16th century to finally allow the correct canon to be known?