Of course revelation knowledge is a gift of the Spirit, and of course Peter understood who Jesus was by that gift. Jesus said as much.
Matt16v17And Jesus answered and said unto him, Blessed art thou, Simon Barjona: for flesh and blood hath not revealed it unto thee, but my Father which is in heaven.
Flesh and blood had not revealed the character of Jesus to Peter, ie no resource of mankind, nor even the man Jesus himself.
Peter's revelation was absolutely revealed by Jesus's Father, and as always, the Father does it by the Holy Spirit, even prior to Pentecost.
None of that is in doubt!
What I am objecting to is that you wrongly extrapolate that fact into the next statement of Jesus.
18And I say also unto thee, That thou art Peter (petros/pebble),
and upon this rock (petra/rock, mountain)
I will build my church; and the gates of hell shall not prevail against it.
Peter correctly understood that Jesus was the Christ, son of the living God. But the general understanding of the disciples regarding the true nature of Christ still remained very flawed.
They expected a warrior king like David, which is why they pressed him right to the very end over whether he would deliver the kingdom back to Israel, ie. drive the Romans out of the land!
In calling himself "The Rock", Jesus was taking Peter one huge leap further than his initial revelation, He was applying to Himself the name of Jehovah God as used throughout the OT!
Additionally, the disciples were also familiar with the Greek word for "church", "ekklesia". They were familiar with that word because it was the word used throughout their scriptures to describe the congregation of Israel itself, not some new creation in the future.
So when Jesus tells Peter that He would build his church/congregation/assembly on the Rock it was an absolutely clear claim to Jesus being Jehovah, the creator God of the Old Testament. The mighty God who led Israel out of Egypt.
To claim that the word Rock refers to one truthful revelation that Peter was given, blinds people's eyes to one of the most significant revelations of scripture.
That's why Satan has placed so many false trails around this piece of scripture!