The only choice they had which would have allowed them assume any other role was conversion to Islam.
> no evidence that this ever happened
There is obviously evidence and there several major Jewish or Samaritan revolts until the Romans lost Palestine in the 600s with the last revolt being quite brutal.
Of course the scale of expulsions, forced conversions and massacres is not really known but the region was almost certainly majority Christian by the time the Muslims got there
> there was a huge jewish diaspora before that revolt and even before the 1st century revolt
There is no strong evidence of that either (depending on how one defines “huge” of course)