The ‘Bolsheviks were Jewish’ story is sourced in Germany (check out Alfred Rosenberg).
Thinking about Jew-hate in Tsarist Russia, it’s unlikely many ethnic Russians would accept Jewish leadership. Jews there, on the other hand, could eagerly hope to ease the persecution of the Church and Tsar.
Jews like Osip Minor and Grigori Kipen make an interesting study, while Jewish military cadets were on the front line battling the Bolsheviks, who also had Jews on their side.
Jews practically invented the idea that there’s something wrong with the way things are, which is why Jews might be right-wing but are seldom ‘conservative’ politically.
I can’t speak for the historical Bolsheviks, but many of the Bolshie radicals I’ve encountered in the US have been.
There are conservative Jewish people, though, to your other statement. Old line southern Jewish families are very close to assimilated but attend Temple regularly. They’re conservative in a way that is immediately recognizable. The history of their state, the south and the nation is their history.
Orthodox Jews of more recent vintage are conservative, too. Maybe not so easily recognizable as such in an American sense, but they’re allies. Their conservatism stems from a Torah derived sensibility as does our own albeit through a different route.