I think Paul was definitely a figure in history, because we have his writings, and they seem genuine.
Earlier, you wrote:
Yes, I put all the Pauline epistles as post-70. And authored by Paul or an amanuensis.
You seems undecided about the authorship of Paul's epistles.
BTW, not all epistles attributed to Paul are genuine (example: the Pastorals). And even the considered genuine letters have been edited (Corinthians and Philippians), and added up with later interpolations.
(Jerome says he flourished after the War.)
Where did you read that in Jerome's works? Jerome had Paul's public life much earlier.
The only possible source of earlier foundation is Tacitus who was probably relating stories he had heard from Christians or Jews, and is therefore unreliable.
"probably" and why "only possible source". Please note Suetonius also mentioned Christians were existing in Rome under Nero:
16.2: "Punishment by Nero was inflicted on the Christians, a class of men given to a new and mischievous superstition."
We also know that founders of religions like to push back their myth of origins in time. This makes them seem more legitimate. We see this with Mormonism, Islam, Judaism all the major religions and some minor ones. So it would be surprising if the early Christians did NOT push back their myth of origins in time.
There is always exceptions to a perceived rule, breaking down any generalization.
Same argument used by Carrier: all ancient gods were mythical, so Jesus was mythical also.
All US presidents were white men, so Obama was white also.
The other thing is argumentation. Arguments from analogy are good arguments.
Not so, as I demonstrated above.
Someone like Pliny is a good source. "Luke" is a bad source. Paul's letters are good sources. The gospels are bad sources.
Good sources can contain false data (such as for Paul's letters: later editing, interpolations and fake ones (like the Pastorals).
on the other side, bad sources can contain good data.
You cannot generalize.