Here’s an idea for a leftist fantasy novel I came up with: A prince/princess of some fairy tale style kingdom is sent abroad on a diplomatic mission, ends up having their propaganda bubble popped, learns about communism, and vows to enact worker rule once their parents die. Once they come into power, how might they set about this if they started from a feudal society, while making sure counter revolutionaries (in this case, like nobles, clergy, other members of the royal family, etc) don’t reverse what they’re doing?
Have you seen Legends of the Galactic Heroes? One of the main characters, Reinhard von Lohengram was born in a monarchy, him being a poor noble. He escalated positions in the military until he became the Kaiser, and omce he got there he took the land from the nobles and gave it back to the people, and also in one episode he mentions they should give the power over the means of production of a sector (I think it was agrary) to the people. While he is certainly not a communist, some of his politics are certainly socialists, and I think it can work very well for your purpose.
He’d be supported by the Soviet Union; it’s not unheard of for the CCCP to have a policy of sorting certain feudal and bourgeois forces in order to advance the revolution.
It is not canon with our history, tho, he lives in Odin and Earth does not have a central political role in their stellar systems.
Never watched Legend of the Galactic Heroes, though I probably should sometime as I’ve heard good things.