Jay53,
Power plays are exactly what we’re talking about. If Diotrephes was making a “power play”, which it sounds like he was, then that is not going to be a one-time event from one single person in all of the early church history. Just because others aren’t noted in the writings we have (besides some Pharisees), does not mean there weren’t others who made “power plays.” That would be a big deal, not an issue of “clashing personalities.”
I still don’t see how this leads to a loss of priesthood authority. You seem to be just dismissing the fact that there were no issues of doctrine or belief. Everyone in the Church was teaching and believed the same thing (which is not what Joseph Smith taught hundreds of years later.)
John would not “not want to” be the living apostle who would be recognized as the leader of the church. Read Revelation 1-3. He is writing as though he knows he is the leader of the church, and encouraging the members of the different cities. It is not as though he was stepping out of the picture. He held the keys of apostleship, which he was the last to hold on earth. Of course he would know he had a responsibility of leadership, and would not simply decide he “didn’t want to”, especially given the example of Peter whom he knew intimately. It is a ridiculous belief (pardon the strong word) to think that John would not accept the role and assignment of being the last living apostle and therefore the holder of apostolic keys of leadership and therefore the leader of the church on the earth.
This makes no sense to me.

Your explanation here sounds more like “sour grapes” because John wasn’t given primacy in the Church. Jesus called us to be servants. IMHO, I honestly don’t think John would care that he wasn’t given primacy.
I think these verses are appropriate: Mark 10:39-45
“We can,” they answered. Jesus said to them, “You will drink the cup I drink and be baptized with the baptism I am baptized with, 40but to sit at my right or left is not for me to grant. These places belong to those for whom they have been prepared.”
41When the ten heard about this, they became indignant with James and John. 42Jesus called them together and said, “You know that those who are regarded as rulers of the Gentiles lord it over them, and their high officials exercise authority over them. 43Not so with you. Instead, whoever wants to become great among you must be your servant, 44and whoever wants to be first must be slave of all. 45For even the Son of Man did not come to be served, but to serve, and to give his life as a ransom for many.”
In reading some of the other posts here it also seems like Mormons think John should have had primacy because of Revelations and his visions. I’d like to here more about this -scriptural support for the fact that only the person in primacy can receive any kind of revelation from God.
You used the word “conspiracy”, not I. If that word fits, then I think that kind of situation applied later when someone was trying to legitimize their own position or the leader of Rome’s position as what came to be called the “papa” or the “Pope”. Study the steps leading to that declaration, and one will see a process of legitimizing the “supposed” passing on of the reins, but neither Peter nor Paul wrote about it in that way.
That’s what I’m trying to figure out. I need you to give me these “steps” that somehow led the Church astray because in reading about Church history I don’t see it anywhere. I used the word conspiracy because John was still alive at the time Peter and Paul gave the primacy to Linus. If it was such a big deal that John should have been given primacy, then St. Peter and St. Paul are to blame for all of that.
Here’s an interesting article if you have time to read it.
therealpresence.org/archives/Papacy/Papacy_014.htm