So Doudna:
The conversion and visit to Jerusalem itself I think may read as ca. 66 and 69 CE, corresponding to Josephus’s “Saulus”, the noble herodian gangster who with cohorts was involved in organized crime in the early 60s. In 66 Saulus, as one of the well-connected “men of power”, visits Jerusalem and leaves as part of a delegation in association with Philip b. Jacimus, commander of king Agrippa’s horsemen (= Philip the hellenist leader in the book of Acts). The Jerusalem visit of Paul of Gal 1-2 may be 68 or 69 CE, with Saulus at that point in the company of Titus and Josephus and representing Roman interests in the siege of Jerusalem, with Saulus as part of a diplomatic meeting with leaders of the Revolt.
(my bold)
The sense of Galatians 2 is really something as: for diplomatic reasons, I am obliged to talk with them as "so-called" Rulers of Jerusalem, even if I deny the legitimacy of their power on Jerusalem, since Jerusalem is property of Titus.
The meeting ended with a nothing de facto: the Pillars wanted Judea for themselves, the Romans had limit themselves to rule only the rest of the world. Which means (for Titus): PROSECUTION OF THE WAR.
Only, the 3 Leaders of the Revolt warned Paul: even if he was their enemy (the diplomacy being failed), he had to remember the fate of the 'Poors', meaning: the people of Jerusalem who couldn't combat (as old people, women and children).
Obviously, the first visit of Jerusalem (Galatians 1) is probably a Christian interpolation Acts-based (a point, the only point, I had conceded to Detering, reading his Falsified Paul).
I like a lot this reading. It makes sense.