Again, we believe the Sacraments are a way of receiving His Divine Grace, not the only way, but the most important way.
You say superstition, I say Faith. Faith in the core teachings of the Catholic Church, the Sacraments, The Ten Commandments, The Bible, Tradition, tradition, the teachings of the Early Fathers
At the time of the split, the “Church” was in a secular mess, not because of these core beliefs, but because some? many? of the Catholic clergy had become followers of materialism and secularism and had lost their own Faith. Catholic clergy are not infallible as men, they can make mistakes. But if what they teach rings true in matters of faith, dogma and doctrine, with the Magisterium, what they say is true and worthy of belief. Much of what was said and done during the time you speak of was fallible,(superstition), but much was also infallible, however taken in the manner of superstitious beliefs by many uneducated people.
So I say those who saw the debaucle the Church had become, at that time, because of the actions of much of the clergy and their humanistic self serving attitudes, lost Faith in what was true, their faith and belief in the words of Christ. Martin Luther saw much that was wrong with the secular government of the church, not the beliefs, ( read indulgences for one item) and wanted to do something about it. Well, look what happened, the Church ignored him, he went further and further away from the Church’s teachings, because after all, he was human too. And thus the BIG split.
Now, other than personal interpretations, what truths do most of the Prostestant denominations hold? How much of what is believed can be proven in any manner other than personal interpretation? There are many Methodist, Presbyterian, Lutheran etc.denominations that exist. Many congregations of the same denomination do not agree with the others. I am talking groups, not individuals, because I know many Catholics who do not agree with what the Chruch teaches. We call them Cafeteria Catholics because they pick and choose according to their conscience what they want to believe and what they don’t. Is this Objective truth in action? No, it is a subjective way of reasoning that leads to individual “thinking”, but not necessarily TRUTH.