Did the apostles often start, teach, and visit churches, training them in Jesus-biography?

Throughout the gospels and Acts, we see Jesus proclaiming that the 12 apostles will be Jesus’s witnesses to the world; Jesus prophesied that they would teach the world of his life, ministry, death, and resurrection. • Lk 21:12-13 —‘But before all these things, they will lay their hands on you and will persecute you, delivering you to the synagogues and prisons, bringing you before kings and governors for My name’s sake. It will lead to an opportunity for your testimony.
• Lk 24:45-48 — [Jesus said], “So it is written, that the Christ would suffer and rise from the dead on the third day, and that repentance for forgiveness of sins would be proclaimed in His name to all the nations, beginning from Jerusalem. You are witnesses of these things.
• Mt 10:18 — and you will even be brought before governors and kings for My sake, as a testimony to them and to the Gentiles.
• Mk 13:9-13 — ‘But be on your guard; for they will deliver you to the courts, and you will be flogged in the synagogues, and you will stand before governors and kings for My sake, as a testimony to them. The gospel must first be preached to all the nations. When they arrest you and hand you over… Brother will betray brother to death, and a father his child; and children will rise up against parents and have them put to death. You will be hated by all because of My name,….
• Acts 1:8 — but you will receive power when the Holy Spirit has come upon you; and you shall be My witnesses both in Jerusalem and in all Judea, and Samaria, and as far as the remotest part of the earth.”
This is relevant because it is highly unlikely authors would be attributing overtly false predictions to Jesus. The authors at least believed the apostles were actively teaching, and their belief on the matter would likely be justified rather than random. And being a witness, of course, involved testifying of Jesus’s fulfillment of Messianic prophecy, his teachings, His death, and His resurrection.

Peppered throughout the book of Acts are rich and loud proclamations of the apostles working essentially full-time to teach about Jesus’s life, ministry, death, and resurrection. Consider these verses:
• Acts say the apostles were devoted to teaching “the word.”¹
• Acts 2:32 — It is this Jesus whom God raised up, a fact to which we are all witnesses.
• Acts 3:15 — but put to death the Prince of life, whom God raised from the dead, a fact to which we are witnesses.
• Acts 4:20 — for we cannot stop speaking about what we have seen and heard.”
• Acts 5:32 — And we are witnesses of these things; and so is the Holy Spirit, whom God has given to those who obey Him.”
• Acts 10:39-41 — We are witnesses of all the things that He did both in the country of the Jews and in Jerusalem. They also put Him to death by hanging Him on a cross. God raised Him up on the third day and granted that He be revealed, not to all the people, but to witnesses who had been chosen beforehand by God, that is, to us who ate and drank with Him after He arose from the dead.
• Acts 13:31 — and for many days He appeared to those who came up with Him from Galilee to Jerusalem, the very ones who are now His witnesses to the people. This is relevant because Acts is the historical document, written during the life of the witnesses, which records how the apostles of Jesus proceeded to live after his crucifixion. And, as seen above, it is peppered with references to the apostles acting as witness-teachers of Jesus’s life, ministry, death, and resurrection.

We read both in 1 John and 1 Peter assertions that the apostles act as witnesses to Jesus's life and ministry. • 1 Jn 1:1-3 — What was from the beginning, what we have heard, what we have seen with our eyes, what we have looked at and touched with our hands, concerning the Word of Life— 2 and the life was revealed, and we have seen and testify and proclaim to you the eternal life, which was with the Father and was revealed to us— 3 what we have seen and heard we proclaim to you also, so that you too may have fellowship with us; and indeed our fellowship is with the Father, and with His Son Jesus Christ.
• 1 Peter 5:1 — Therefore, I urge elders among you, as your fellow elder and a witness of the sufferings of Christ, and one who is also a fellow partaker of the glory that is to be revealed: This is relevant because these, along with the other sources above, all converge on the same truth, with no evidence of dissent.

Irenaeus, writing in c. AD 185 records how Clement (c. 30-100 AD) was a disciple-student of the apostles, being specifically taught by them. • Irenaeus (writing c. AD 185): “Clement [c. 30-100 AD, bishop of Rome] was allotted the bishopric. This man, as he had seen the blessed apostles, and had been conversant with them, might be said to have the preaching of the apostles still echoing, and their traditions before his eyes. Nor was he alone, for there were many still remaining who had received instructions from the apostles. In the time of this Clement, no small dissension having occurred among the brothers at Corinth, the Church in Rome dispatched a most powerful letter to the Corinthians [Written c. AD 95].” [Against Heresies 3.3.3] This is relevant because this very specific belief of Clement’s an Irenaeus’s is likely not a complete shot in the dark, but rather is likely to enjoy some measure of justification. (They were up close to the events.) It is also one of the few resources, aside from Acts, which speak on the matter.

The Jerusalem church pass-down Jesus-bio, delivering to their successors and even other churches. This is relevant because the apostles lead the Jerusalem church, and the apostles passing down this content in part explains the fact that the Jerusalem church passed down Jesus-biography.

In the 1st century, while witnesses were still alive, the number of people converting to believing in Jesus's claim to be Messiah as well as his resurrection was massive. This is relevant because it is near impossible to explain if Jesus’s own apostles abandoned the faith or were otherwise lacking zea in their teaching of others. The growth is far easily to explain if they apostles were actively teaching.

The earliest Christians honored the “The Twelve” (apostles) as leaders of all Christendom, as long as those apostles were still alive and active. This is relevant because it is hard to explain unless the apostles were witness-teachers.