What’s the model of St. Augustine?
That Apostolic succession is transmitted regardless of the ecclesial standing of the bishop; it was part of his argument against the Donatists.
St. Cyprian of Carthage insisted that only Orthodox bishops could transmit Apostolic succession.
Who says this is only about taxes? My recollection is that this was an issue about his image, that is, what belongs to Caesar.
The three Synoptic Gospels - those according to St. Matthew the Apostle, St. Mark the Evangelist, and St. Luke the Evangelist.
Specifically, quoting from the Gospel According to Mark, Mark ch. 12, v. 13 - 17
13 Later they sent some of the Pharisees and Herodians to Jesus to catch him in his words.
14 They came to him and said, “Teacher, we know that you are a man of integrity. You aren’t swayed by others, because you pay no attention to who they are; but you teach the way of God in accordance with the truth. Is it right to pay the imperial tax b to Caesar or not?
15 Should we pay or shouldn’t we?” But Jesus knew their hypocrisy. “Why are you trying to trap me?” he asked. “Bring me a denarius and let me look at it.”
16 They brought the coin, and he asked them, “Whose image is this? And whose inscription?” “Caesar’s,” they replied.
17 Then Jesus said to them, “Give back to Caesar what is Caesar’s and to God what is God’s.” And they were amazed at him
In other words, it relates to paying taxes to the legitimate government authority, whoever that is.