No amount of proof will ever be sufficient but don't stop rebuking. To use a military term, this is a hill Protestants are willing to die for. Once they admit that Peter was the first Pope and that Catholic Apostolic Succession is proven their fig leaf is removed and they will have to stand before the world and their maker as naked heretics.
"For such is the will of God that by doing right you may silence the ignorance of foolish men." - 1 Peter 2:15
My frustration with protestants is not that they claim as valid their interpretation of Scripture, relying on the promise to be led into all truth by the Holy Spirit as their authority.
It is that they make the same claim as the Church in that regard, yet ridicule and disparage our beliefs, which are supported by Scripture in every instance.
If a Catholic gives them verses to show that Scriptural support, we are told that our interpretation is wrong and again ridiculed as being ignorant or brainwashed or whatever derogatory term they think to use at the time.
I will not be discouraged from defending my faith by their derision, and in most cases find that I am strengthened by that very defense.
If I did not gain from these exchanges, I would not engage in them. God has made good for me a situation which can often leave me exasperated but enlivened further in my faith.
I have no need to prove anything to them, their conversion is a matter of the work of the Holy Spirit, I just can’t remain quiet in the face of false and misleading statements.
Bwahahahahaha! The only thing Peter did in Rome was die. Maybe. Hehe Since they found the sarcophagus that can’t even be proven.