And on top of what AMPU said, you still have no evidence that Paul is speaking of the Roman Catholics.
I would think that a ‘foundation of truth’ would be something completely in line with what the Lord has said, not one who has to resort to infallibility doctrines for their theology.
Yes, Revelation writes of churches or cities ... and technically I am a member of the Church of Richmond.
So, is Christ the head of several bodies, the husband of several brides? What are the hermeneutics for knowing when Paul (or anybody) is speaking of the universal church and when he is speaking of the local one?
I do not see the words “local” or “sometimes.” That doesn't mean your suggestion is wrong. But it's not self-evident either.
Also, if the only local church is the pillar and foundation of truth, when it teaches properly, how, especially before there was a canon of Scripture, does one tell if it's teaching properly? How does one tell if it decides properly in choosing the canon?
If a local congregation chooses, as some “Orthodox” do, to stay away from Revelation or to admit the so-called apocryphal books, how does one argue for or against that?
Or if the local Church is Arian, or Docetist, Monophysite, Monothelite, icon-favoring or iconoclastic, where does one go for authority?
In a small town like Columbus Mississippi when I was there there were several local churches of different kinds. Over here abortion was said to be wrong. Over there it was said to be up to the mother.
Sure, there's the “tradition,” shown in the Didache, of ... well I guess you all would say “somebody, somewhere,” saying abortion is wrong, but the Didache is maybe 90-110 AD and not Scripture. So I suppose it's just an opinion of the local writer who may or may not be right, for his local church.
Believe me, I don't jump up and down and clap my little paddy-paws at the idea of conciliar or papal infallibility. But I see many long and cogent writings claiming to be based on SOME version of Scripture but saying contradictory things.
It doesn't seem to me to be so very clear.