“It’s not recorded anywhere where Jesus told His disciples to write with the clear exception of John on Patmos.”
A point of correction here.
You might learn to read a bit closer:
“sending his angel to his servant John”
1 The revelation of Jesus Christ, which God gave him to show his servants[a] what must soon take place; he made[b] it known by sending his angel to his servant[c] John, 2 who testified to the word of God and to the testimony of Jesus Christ, even to all that he saw.
When I saw him, I fell at his feet as though dead. But he laid his right hand on me, saying, Fear not, I am the first and the last, and the living one. I died, and behold I am alive forevermore, and I have the keys of Death and Hades. Write therefore the things that you have seen, those that are and those that are to take place after this.
Jesus is speaking here.
The first and the last, the one who died and alive evermore.
That is NO angel.
9 I, John, your brother and companion in the suffering and kingdom and patient endurance that are ours in Jesus, was on the island of Patmos because of the word of God and the testimony of Jesus. 10 On the Lords Day I was in the Spirit, and I heard behind me a loud voice like a trumpet, 11 which said: Write on a scroll what you see and send it to the seven churches: to Ephesus, Smyrna, Pergamum, Thyatira, Sardis, Philadelphia and Laodicea.12 I turned around to see the voice that was speaking to me. And when I turned I saw seven golden lampstands, 13 and among the lampstands was someone like a son of man,d dressed in a robe reaching down to his feet and with a golden sash around his chest. 14 The hair on his head was white like wool, as white as snow, and his eyes were like blazing fire. 15 His feet were like bronze glowing in a furnace, and his voice was like the sound of rushing waters. 16 In his right hand he held seven stars, and coming out of his mouth was a sharp, double-edged sword. His face was like the sun shining in all its brilliance.
17 When I saw him, I fell at his feet as though dead. Then he placed his right hand on me and said: Do not be afraid. I am the First and the Last. 18 I am the Living One; I was dead, and now look, I am alive for ever and ever! And I hold the keys of death and Hades.
19 Write, therefore, what you have seen, what is now and what will take place later. 20 The mystery of the seven stars that you saw in my right hand and of the seven golden lampstands is this: The seven stars are the angelse of the seven churches, and the seven lampstands are the seven churches.