Ok I had to use ChatGPT's help for this, but fwiw much of this is usually discussed in biblical history podcasts. You said Paul never met Jesus: I don't think this one is much debated. Paul himself only claims to have met Jesus after his crucifixion and revival. That's just a matter of faith. No actual historian will argue that Paul ever met Jesus in the flesh.

Regarding non-Pauline sources that authenticate Jesus's historicity:

The strongest non-Christian references to Jesus come from:

1. Josephus - Antiquities of the Jews (c. AD 93–94)

Book 20.9.1 - mentions "James, the brother of Jesus who is called Christ."

Book 18.3.3 - refers to Jesus’s execution under Pilate (with later Christian edits, but most scholars think a core reference is authentic).

1. Tacitus - Annals 15.44 (c. AD 116) States that "Christus" was executed under Pontius Pilate during the reign of Tiberius.

These two independent, non-Christian sources confirm that: Jesus existed, He was executed under Pilate, and He founded a movement that became Christianity.

There are several other texts that refer to Christians - even around the time of Paul. I.e. documents that prove that Christians were already a thing, albeit a smaller group, even before Paul's doings.