Sola Scriptura, or as I like to call it "the sufficiency of scripture", is an extremely powerful defence against the wonky theology of the Catholic Church. Whenever the Catholic Church makes stuff up, we as Christians can simply reply "God did not say that, you said that". And so, we do not have to believe any dogmas the Catholic Church spits out.
The sufficiency of scripture is an irrefutable fact. The Bible teaches Sola Scriptura, the early Church believed Sola Scriptura, and on top of that, it is just common sense. However, getting a Catholic to admit that is not easy. Thankfully, although it is a powerful weapon against Catholicism, it is not absolutely necessary.
The Dogmatic Constitution on Divine Revelation, which was promulgated by Pope Paul VI in 1965, states "Therefore both sacred tradition and Sacred Scripture are to be accepted and venerated with the same sense of loyalty and reverence." (Emphasis mine).
Because of this statement, Catholics are not allowed to revere the Bible as being less authoritative than their traditions. Already, this is problematic for them, as it puts scripture on equal footing with Catholic teaching. When the Bible and Catholic tradition do not agree, Catholics cannot say "well, tradition interprets scripture". That is not accepting or venerating the Bible with the same sense of loyalty and reverence as tradition, but revering scripture as being less than tradition.
But it gets worse, because the Bible tells us "All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness, that the man of God may be complete, thoroughly equipped for every good work." (2 Timothy 3:16-17). This verse, in and of itself, causes a massive headache for the Catholic Church. On its own, it proves Sola Scriptura. And of course, as I have just pointed out, the Catholic Church cannot undermine this without contradicting its own dogmas. But as I said, we do not necessarily need Sola Scriptura, because this verse tells us something else about scripture: It is given by inspiration of God. This, of course, is affirmed by the aforementioned Dogmatic Constitution on Divine Revelation.
Now, this is going to be a no-brainer: When God says something, and tradition disagrees, who wins? Anyone who says tradition can join the Pharisees in Hell, for it is this very error for which the Lord rebuked them. These were men who strongly valued their tradition, even to the point of setting aside God's word, to their shame. Jesus rebuked them constantly for this, and as a result, they nailed Him to a cross. Now, if the scriptures are superior to tradition, according to none other than Jesus Christ, who wins when the Bible disagrees with the Catholic Church?
The Catholic Church disagrees with the Bible on a number of issues. Sola scriptura, the importance of works in salvation, the role of Mary, the Papacy, the existence of Purgatory, and so much more. Thus, we see that even without establishing Sola Scriptura, the Catholic Church is a demonstrably heretical organisation. Catholics need to repent, and flee the Catholic Church as swiftly as they would flee sexual immorality. Many Catholics may not even be saved, though I take the position that there are true Christians in every denomination. Those who are saved, leave Catholicism, literally for Christ's sake. Those who are not saved, get saved, lest as you join the Pharisees in their sin, you also join them in their punishment.