‘The Catholic faith’ doesn’t believe anything. It can’t. A concept has no life unless it is personified. It’s Catholic people who make up the community of the faithful and who have communal and individual beliefs. Catholics own their Catholic faith. Even so, such thinking implies that there is a unified body of Catholics who have a universal way of life- which is contradicted by a fact as simple as the existence of party politics in America. You have Catholics on both sides of issues the Church has declared morally intrinsic to the faith - birth control, abortion, capital punishment, etc.
In my opinion, the mass offers the truth in the form of sacrament. We receive Jesus, who was completely undivided. Speaking for myself, I hope he gives you more understanding.
When you say you have gotten not very much understanding, how can you be sure about how much that really is? A statement like yours indicates to me that me that you want full understanding, and you want to know you have full understanding. Full understanding of the Catholic faith is a mystery solved in community, and, importantly, according to community rituals and sacraments. One could argue persuasively that there is no full
understanding of the Catholic faith, but rather, full participation in Catholic life.
I believe it was in his book “Crossing the Threshold of Faith,” that PJPII was asked “How
does the Pope pray?” His answer as I recall was “Ask the Holy Spirit!”