Personally, I think you are setting up a straw man argument when you insist on an either / or scenario. It is not either Scripture is sufficient or Tradition. There are no Catholic teachings that I know of that are not at least implicit in the two Testaments of Scripture.
Mary had to be sinless. Look at all of the concern with the purity of the Ark in the OT, and the matter becomes plain. Remember Uzziah? What was contained in the Ark? The Bread of Life, God’s Word and the symbol of the High Priest in Moses’/Aaron’s staff that grew? Who is the Bread of Life, Word of God, and High Priest of the New Covenant and where did He reside for nine months? (Reread both the Visitation in Luke 1:39-52 and 2 Samuel 6:4-16).
Infant baptism? When did the Israelites, by God’s command, bring their children into the covenant? At the ripe old age of eight days. Being called by God has always been through grace alone, consent comes as we accept and persevere in our faith, but it is always initiated by God. It is not surprising that most of the baptisms were of adults first, as it was a New Covenant, but most households in that day included spouses, children, servants, and slaves. It is not surprising that we continue to baptize all ages.
Mary as the New Eve makes perfect sense if you are aware of Jesus as the New Adam, and are conversant with Davidic Kingdom (and Middle East) customs whereby having one wife reign over all the others would lead to intrigue and possible death. It was the Queen Mothers who ruled as Queen instead. Who did Abimelech go to in order to try to wrest the kingdom from Solomon? The Queen Mother–Bathsheba, though she did not gain her request. Like so many OT foreshadowings, they were perfected in the new when the Queen Mother asked her Son to provide wine for a wedding feast. Jesus is the head of the Church, Mary is the Mother of the Church. Look to Revelation and the end of John at the foot of the Cross for hints of this.
As for Liturgy not being in the Bible, I suggest you reread Exodus and Revelation again. It is all there, though not spelled out. Priestly robes, incense, altar and sacrifice, OT readings, psalmic readings, even the prayer over the bread and wine is very similar to ancient Jewish formulations. Why would God not spell it all out? Where in the OT do you see the Jewish liturgy spelled out? Ours is very close to theirs with the addition of the once for all sacrifice, the todah sacrifice that Jesus gifted us with.
I really don’t know why God chose to do it this way, but I do know that all through the OT and even the New, that we are told that we must have eyes to see and ears to hear.
St. Peter even warns us how St. Paul’s words were misinterpreted, and Luke showed us how the Ethiopian need Nathaniel to interpret Scripture for Him. So even the Magisterium is found there. Just as the Trinity is present at Jesus’ Baptism, which he tells us to use to save people and bring them into the fold.
There is so much subtlety in the teachings and truths of our faith that can be traced to Scripture if we only know how to see it, but we will never see it if we insist on forcing issues into either/or arguments. God is not bound by arbitrary man-made distinctions such as either’or and neither should we be if we are seeking God’s Truth rather than our own.
I am not so proud as to think that I completely understand our theology and make no mistakes, but I do beg mercy as I am only a homeschool mom who has no theology degree, just a strong desire to know and love my Creator and Savior better.
In Christ’s peace and joy,
Robin L. in TX