Neither dare one agree with catholic bishops if by chance they err in anything, but the result that their opinion is against the canonical Scriptures of God. - Augustine De unitate ecclesiae, 10 If this proves Augustine adhered to sola scriptura, you have a big problem on your hands.
Augustine also wrote that one who failed to adore the Holy Eucharist was thereby sinning.
He also wrote an extremely fulsome prayer to Mary.
"For our faith rests on the revelation made to the Prophets and Apostles who wrote the canonical books.- - Thomas Aquinas Summa Theologiae, Question 1, Art. 8
Ditto for St. Thomas
So you have a problem. You have to conclude one of the following X things:
- Oops, Augustine and Aquinas didn't really believe in sola scriptura, or at least what they believed by it isn't what modern Protestants believe by it, so they can't really be cited as support for the Protestant position
- Augustine and Aquinas were incompetent practitioners of sola scriptura, but I, ears_to_hear, am not, so you should listen to me, not to them ... except when I want you to.
- Adoring the Eucharist and praying to Mary are both consistent with sola scriptura
- Nobody can really make up their mind what sola scriptura means, so, at the end of the day, it's not a sufficient rule of faith
He also wrote an extremely fulsome prayer to Mary LOL. If so, on that we would agree.
(Hint: look up the meaning of "fulsome." You're not alone. Most people get it wrong. In this case, however, you're probably closer to the truth.)