I'm not surprised.
Basing an attitude toward the development of doctrine that founded it on doubt that God would protect the Catholic Church from error is what I would never want to answer for.
I think you have the wrong church in mind. The catholic church has been protected and preserved throughout the ages, including the Dark Ages which was the zenith of your church's power. Even at the height of Romes power it could not exterminate those Christians that attempted to hold to Scripture as the rule of faith. A remnant always survived.
A great example of how bad it is to have doctrine "develop" over time is the misplaced over emphasis on Mary. As Mary's role "developed" you see her perpetual virginity being promoted as fact. Mary goes from being referred to as "woman" by Jesus to a "suitable vessel" by Ignatius to "Mother of God" by Origen. All this in about a 200 yr period of "development". Now it is a dogma that RC's must believe that Mary was born without sin and was assumed into heaven. Also, she is supposed to be able to hear millions of prayers simultaneously and discern which are worthy of special attention.
I'll stick to what doesn't change, Scripture.
Ijohn 1:3-4 that which we have seen and heard we declare to you, and truly our fellowship is with the Father and with His Son Jesus Christ. And these things we write to you that your joy may be full. (emphasis mine)
This actually has moral consequences: if the child in Mary's womb is not fully what He was at His birth, then a fetus might not be fully what it is at birth. And so we find ourselves right next door to a pro-abortion position.
Also, she is supposed to be able to hear millions of prayers simultaneously and discern which are worthy of special attention. That to me is unremarkable.
And the interesting aspect, to me, of the disagreement over that ability is its reflection of a difference over what God is and what Heaven is like, specifically as regards time.
And that turns out to be about the role and nature of reason and especially the degree to which reason is corrupted by the Fall.
If reason is utterly unreliable, then we are in a position similar to that held by "orthodox" Muslims with respect both to God and to the Koran.
(This is not a disparaging comment, but a taxonomic one. If I am wrong in my attempt to characterize your view, puhLEEZE don't hesitate to tell me. I spend a lot of time being wrong -- ask my wife.)
That is, we cannot hope to have even the least understanding of God's will and it's goodness, so that (a)He could command us to hate him, and (b) if He did, it would be right to do so.
Similarly, we can never hope to understand the Bible. Our role is to say, "Yessir!" without comprehension.
We think that just as sexual intercourse can be sanctified in a Christian Marriage but can be fertile even if illicit, so reason can HELP us to the truth when it is informed by grace, and even not so informed can lead us to SOME partial (even dangerously partial) truth when it is used in the arguments of the unregenerate.
ANYWAY, Whitehead to the contrary notwithstanding, we find that God, when contemplated by reason alone, is found to be outside of time or timeless, while comprehending time.
Therefore, to be glib, Mary (and all the blessed) have "all the time in the world" to hear, sort, and process petitions. I'm pinging Beleg Strongbow because he is NOT in communion with the Holy See (I think) but still is aware of the scholastic way of thinking. Beleg: this ain't a fight, it's a conversation, a "frank exchange of views," and for that reason quite enjoyable and useful