Jesus tells us:
Jesus chooses who He sends. He can call whomever He wants to send. I do not believe that call is limited to those whom the Catholic Church recognizes.
When a Protestant becomes a minister, he does so because God is calling him to service as much as He calls those who decide to receive Catholic orders.
Authority to call can come from the congregation of a church itself. The Didache gives a guide to early Christian practice.
Didache, Chapter 15
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This would indicate that the early church selected their own bishops and deacons.
Similarly Clement of Rome indicated how the cergy were to be selected.
Clement of Rome (Epistle to the Corinthians, Chapter 44)
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Clement says the clergy is to be appointed by the Apostles or other eminent men and approved by the whole church. He does not limit the eminent men to those appointed by the Apostles.
Tertulian tells us that doctrine is the test of a true church. It is not limited to those having Apostolic Succession.
Tertullian (Prescription Against Heresies, Chapter 32)
newadvent.org/fathers/0311.htm
How do we know what correct doctrine is? Irenaeus tells us that doctrine is handed down.
Irenaeus (Against Heresies Book 3, Chapter 1. Paragraph 1.)
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He tells us it was originally passed on orally but also that it is now handed down through the Scriptures. Tradition has been recorded in Scripture. John Chrysostom tells us the same thing.
John Chrysostom (Homilies on Second Timothy, 9, 3:16-17)
newadvent.org/fathers/230709.htm
If we need to know anything that Paul could have told us, we can find it in the Scriptures.