And, Paul's recitation of the Lord's Supper in 1Cor 11 was not the first they had heard of it. He said in vs 23:
For I received from the Lord **what I also delivered to you**, that the Lord Jesus on the night when he was betrayed took bread...
Right you are!
I'm not saying I am presupposing Catholicism when I read Scripture, I am saying that on Catholicism, Catholicism is being presupposed by the Scripture. The argument from Scripture for Catholicism is like the argument from Scripture for the Trinity, in that, it's a transcendental argument, where you try to prove that unless what is presupposed is presupposed, then the Scripture would not say what it does say. (All this means is that the Bible is not exactly a textbook or a "SOF", which I don't think is controversial.)
btw I want to add here that whatever your convictions about the theology and ecclesiology of the Scripture, you too believe the Scripture presupposes your view. It just means you think your view is correct.
My point about the Trinity Nick is just that, there's no chapter and verse which says, "God is Triune," or, "God is three Persons." The Bible's just not like that in many ways. In some ways, it is, like, for the virgin birth. The Scripture does teach that, and explicitly, but not for everything. Testing what we believe the Scripture presupposes is a transcendental or maybe a Bayesian effort, something which examines passages in light of what we think the Scripture presupposes, and asking, "Is this passage likely, unsurprising under this theology, or is it surprising?"
We should do this with anything we think the Bible presupposes, whether it's Catholicism, Eastern Orthodoxy, MAD, Open Theism, or Enyartism (MAD + OV).