What writings from the ECFs are you aware of dealing with Peter, his primacy, or the papacy in general? I’ve just started reading St. Chrysostom’s works and have found a lot dealing with him, even in places where I didn’t expect to find them. For a few examples, just in the beginning of book 2 of his treatise on the priesthood, he says:
For addressing the leader of the apostles He said, “Peter, lovest thou me?” and when he confessed that he did, the Lord added, “if thou lovest me tend my sheep.” The Master asked the disciple if He was loved by him, not in order’ to get information (how should He who penetrates the hearts of all men?), but in order to teach us how great an interest He takes in the superintendence of these sheep.
For why did God not spare His only-begotten Son, but delivered Him up, although the only one He had? It was that He might reconcile to Himself those who were disposed towards Him as enemies, and make them His peculiar people. For what purpose did He shed His blood? It was that He might win these sheep which He entrusted to Peter and his successors.
Naturally then did Christ say, “Who then is the faithful and wise servant, whom his lord shall make ruler over His household.” Again, the words are those of one who is in doubt, yet the speaker did not utter them in doubt, but just as He asked Peter whether he loved Him, not from any need to learn the affection of the disciple, but from a desire to show the exceeding depth of his own love: so now also when He says, “Who then is the faithful and wise servant ?” he speaks not as being ignorant who is faithful and wise, but as desiring to set forth the rarity of such a character, and the greatness of this office. Observe at any rate how great the reward is—" He will appoint him," he says, “ruler over all his goods.”
Will you, then, still contend that you were not rightly deceived, when you are about to superintend the things which belong to God, and are doing that which when Peter did the Lord said he should be able to surpass the rest of the apostles, for His words were, “Peter, lovest thou me more than these?” Yet He might have said to him, “If thou lovest me practise fasting, sleeping on the ground, and prolonged vigils, defend the wronged, be as a father to orphans, and supply the place of a husband to their mother.” But as a matter of fact, setting aside all these things, what does He say? “Tend my sheep.”
I’m also aware (I can’t find it online to copy-paste, and I don’t want to type it out) that, in his commentary on Matthew’s gospel, he refers to Peter as the “leader of the apostolic choir”, but also that the rock which Jesus spoke of in 16:18 is Peter’s profession.
Feel free to add your own findings.