SFAIK this was a matter of debate within Judaism at the time. The OT doesn’t have much to say about an afterlife, but the few hints that might point to one do become more frequent in the later-composed texts, and by the time we are speaking of it was a widely-held belief among Jews. At the risk of oversimplifying, the Saducees (aligned with the priesthood) either dismissed the possibility of an afterlife or dismissed it as unimportant, while the Pharisees accepted and taught an afterlife (involving resurrection). And during the course of the first and second centuries, with the Roman-Jewish wars, the destruction of the Temple and the Diaspora, the Saducee movement basically collapsed and the Pharisees came to dominate and gave us what we now know as rabbinic Judaism.
So, in the very early period of the Christian movement, they were preaching an afterlife (again, resurrection of the dead) while Judaism was divided on the subject. But, certainly, if you liked the idea of an afterlife and wanted a religion which could accommodate that, you didn’t have to leave Judaism to find that. And from the second century onwards belief in resurrection/an afterlife seems to have been pretty mainstream in Judaism.
So, as I have suggested in the post above, there were factors around that may have worked to encourage Jews to embrace Christianity in the early centuries of the Christian era. But I don’t think that teachings on resurrection/afterlife would have been a big factor there.