I agree with your first paragraph - more than you do.
It makes no difference that the Catholics who worked on the canon were sinful people (as we all are). It’s the **Church **that God protects from error, not the individuals.
And we believe this today, too! When we talk about Catholic teaching, we are talking about the teaching authority of the Church, not the personal authority of the pope or even of the bishops as a group.
Without the authority of the Church, we would have no way of knowing that the canon is correct. This is why the Protestants felt free to change the canon–they didn’t accept the authority of the church.
Of course they like to say that the CC added books, but the evidence is clear that the Septuagint included what was later removed by the Jews (AD 100, or so).
So, the Protestants base their Bible on a Jewish canon that was different from what Jesus was using, and that wasn’t approved until after Jesus’ death.
The only reason for denying the canon of the Bible is denial of the Authority of the Church that Christ founded, in which case who determined the canon, the Catholic Church, does matter to you!