1 Peter 5:13 The church that is at Babylon, elected together with you, saluteth you; and so doth Marcus my son.
Peter was writing from ROME. Babylon is ROME (Catholic system, popery, etc...)
//Peter was writing from Rome so Babylon is Rome.//
My response: That’s an assumption. Jerusalem was Peter’s home base. There is good evidence that Peter was referring to Jerusalem, as explained in this article:
https://donkpreston.com/babylon-in-1-peter-513-rome-or-babylon/
It says the Church AT Babylon, not that the Church there IS Babylon. Babylon here refers to the pagan city of Rome, not the Church.
I see no reason Peter could not be referring to Jerusalem while writing from Rome, do you? It is not as if his connection to Jerusalem had been entirely curtailed. Just saying.
There’s no evidence for that.
Peter didn’t write Revelation, so his use of “Babylon” doesn’t necessarily correlate with that in Revelation.