Are you unfamiliar with that passage in Ephesians, so that you did not recognize the church in it ?
I’m not a Jew, by the way ... :-) ... but a Gentile who is in the assembly of the saved ones, by virtue of the fact that Jesus is the Messiah of Israel, and I have accepted the Salvation provided by him in that regard, per the Scriptures.
So you write, yet Paul writes that those Gentiles who really are in Messiah, are built upon the foundation of the apostles and prophets with Messiah being the chief cornerstone. According to Paul, the foundation is comprised of the apostles and prophets, Messiah being the chief cornerstone. Do you understand what the foundation of a building is, and what a chief cornerstone is ? Do you think the Messiah gave Peter the wrong key to the wrong house ?
When you talk about the “church” (and in light of the three ways I pointed out how people commonly use the word) ... I would say that if you’re referring to what the Bible calls “ecclesia” ... the assembly of the saved ones ... then, yes, I am talking about that. I’m not talking about the other two that the Bible is not talking about either ... the building or the organization.
AND THEN ... in regards to building upon what Jesus has provided, namely that he is the Messiah of Israel ... only Jesus Himself can provide that fundamental beginning ... and no other.
Others can add to the “assembly of the saved” (the “ecclesia”) by spreading the Gospel to all, but without the Salvation by the Messiah of Israel ... there is nothing. It’s either you have that ... or ... you have nothing (no matter who else does what).
To put it in short form ... Jesus say he builds his ECCLESIA (the assembly of the saved ones) from the FACT that he IS THE MESSIAH (the one who was promised by God to come for the salvation of the world).