Radrook ... unfortunately it is a huge task of understanding, and I do consider many Catholics (pretty much all the ones I know) to be my brothers and sisters in Christ (just as I consider Protestants I know to be so).
But ...
An understanding of what the CHURCH has done, how the Catholic Church behaved, believed, and changed in history, and what really happened, would answer many of your questions.
But it is very important to understand that we are not them. They were once part of us, but they separated themselves long, long ago and went their own way (after several centuries of already tending to their own way).
Very often I see confusion, based on assuming that only Catholics and Protestants compose Church history.
The Church did not change so much. It came from Judaism, and certain changes of course happened right away to make them Christian as opposed to Jewish. But because of persecution, for centuries the Church operated in secret. When official persecution ended, the Church operated more openly, but not so differently. Liturgy, for example, originated in Judaism, not with the later development of Catholicism.
Your answers are in these things. I think I understand your questions. I was taught the same things you cite, and believed them for many years. But they come from (1) being unaware of Orthodoxy, and (2) confusing Catholicism and Orthodoxy, for the most part. But it does take a lot of time and study to sort it all out.
I'm not looking to convince you of anything, but to answer your questions. Any real convincing has to come from the Holy Spirit and one's own understanding. So I never want to argue, but anytime I can answer questions, at least as far as what I've learned myself, I'm always happy to try. But what one does with the answers is always between them and God.
God be with you, my brother.