Not sure they would have been able to hold off Rome indefinitely. Possibly come to an agreement where they pay a certain amount of tribute in exchange for being semiautonomous.
There wasn't a strong enough counterweight to Rome for them to use as a protector (and from a theological standpoint, that would have failed anyway as they would be trusting man rather than YHWH for protection).
If they had managed to gain independance, would there not have been a lot of objections to being a Roman client state, as the whole goal of the Revolt was to throw off Roman authority? And OTL both the Jews and the Parthians were significant thorns in the Roman’s side, so they might be able to find a common enemy in that?
And that in turn would require a fundamentally different Bar Kokhba revolt.I just don't see a way for them to gain independence and make it stick. The odds are better for forcing the empire to give them a better deal.