Apologists do not just say the NT gives us multiple first-hand accounts of the resurrection of Jesus, they also assert that the first-hand nature of these accounts is “clear”.  At least the more fundamentalist of them argue that way.

The gospel we today call “John” contains various assertions that Jesus was seen alive after he died, here is one example:

 14 When she had said this, she turned around, and beheld Jesus standing there, and did not know that it was Jesus.
 15 Jesus said to her, “Woman, why are you weeping? Whom are you seeking?” Supposing Him to be the gardener, she said to Him, “Sir, if you have carried Him away, tell me where you have laid Him, and I will take Him away.”
 16 Jesus said to her, “Mary!” She turned and said to Him in Hebrew, “Rabboni!” (which means, Teacher).
 17 Jesus said to her, “Stop clinging to Me, for I have not yet ascended to the Father; but go to My brethren, and say to them, ‘I ascend to My Father and your Father, and My God and your God.'”(Joh 20:14-17 NAS)

This gospel is believed by most fundies to be authored by John himself, but some fundie commentaries refuse to bluntly state that John was the author, and instead conclude that an apostle John was connected to the writing of that gospel:

The former series was authored and edited by scholars committed to the infallibility of Scripture, making it a solid foundation for the present project. In line with this heritage, all NAC authors affirm the divine inspiration, inerrancy, complete truthfulness, and full authority of the Bible. The perspective of the NAC is unapologetically confessional and rooted in the evangelical tradition.  Borchert, G. L. (2001, c1996). Vol. 25A: John 1-11 (electronic ed.). Logos Library System;  The New American Commentary. Nashville: Broadman & Holman Publishers.                               To conclude this section on authorship, it seems to me that when all of the arguments both internal and external are set together, there seems little reason to reject the idea that the son of Zebedee was the towering figure and the authentic witness involved in the writing of this Gospel. Borchert, G. L. (2001, c1996). Vol. 25A: John 1-11 (electronic ed.). Logos Library System;          The New American Commentary (Page 90). Nashville: Broadman & Holman Publishers.

How much of the material in John’s gospel, which tells the story of Jesus appearing alive after death, draws upon an apostle John’s own eyewitness memories, and how much of it draws on something else, and what criteria do you use to distinguish the former from the latter?

Apologists cannot cite the gospel of John as first-hand testimony to the resurrection of Jesus, until they answer those questions.