It’s interesting how the focus of the passage is so often on Peter and his name change and not on Jesus and His being the Messiah. It elevates Peter to a position that is not warranted, and diminishes Jesus.
But that would be like the enemy to take the focus off Jesus and what He did for us, and put it on a man instead.
ANY teaching that diminishes Christ and His work on the cross is from the enemy. He simply does not want people to go there because Jesus told us that if He were lifted up, He would draw all men to Himself.
You are correct, the focus must be changed to distort the message.
Joshua also talks about this place, then called Baal-gad (hope that is correct). At one time it was the worship place of Gad, Rob, Tristr, and later Pan.
My imagination says that Christ stood at the gates of Hell - Ceaserea Philippi - where many dead gods had been worshiped to have the truth spoken!
BTW we get the English word ‘panic’ from the Greek idol pan.