10% of the residents of the Roman Empire were Jewish circa 4 BC. The vast majority of those Jews were neither born, nor lived, in Palestine. Onwards.
Roman rule rubs the Al Qaeda faction of the Judea Jews – they preferred the name “zealots” – the wrong way. There are constant rebellions. Zealots claimed control of Jerusalem by heathen rulers was offensive to God. How many people supported them, and how many opposed them? Excellent question, to which we have no good answer. Obviously the elite opposed the zealots and the idea of war with Rome.
In 70 AD Roman armies set the Temple ablaze. If that was offensive to God, he left no comment. From that point onwards, Judaism did not have a center. There was, however, no exile.
I’ll repeat it: there was no exile.
Judean Jewry continued to exist. Sixty years later, there would be enough angry Jews there for another rebellion, The Bar Kochva debacle. But, again, there was no exile. And 70 years later, the Jewish community in Judea was in its finest bloom: the collaborationist elite would write the Mishnah, there would be previously unknown wealth all over the place, and new synagogues everywhere.
Whereupon we reach the calamitous 3rd Century AD, and the empire begins to collapse. By the end of the 4th century, most Jews of the empire would disappear. There is only one recorded pogrom. We can safely assume they did what many Pagans did: they converted to Christianity.