To be annoyingly accurate, Marx still held the belief that the west would be the first to revolt and establish socialism

And he literally contradicts this, not just in this but his other research and letters, and even later editions of the communist manifesto.

https://monthlyreview.org/articles/marx-and-engels-and-russias-peasant-communes/

“The very existence of the Russian commune is now threatened by a conspiracy of powerful interests,” he noted—but if that threat is defeated, it “may become the direct starting-point of the economic system towards which modern society is tending; it may open a new chapter that does not begin with its own suicide.”14

Marx and Engels repeated that argument the next year in their preface to the second Russian edition of the Communist Manifesto.

In Russia we find, face-to-face with the rapidly flowering capitalist swindle and bourgeois property, just beginning to develop, more than half the land owned in common by the peasants. Now the question is: can the Russian obshchina, though greatly undermined, yet a form of primeval common ownership of land, pass directly to the higher form of Communist common ownership? Or, on the contrary, must it first pass through the same process of dissolution such as constitutes the historical evolution of the West?

The only answer to that possible today is this: If the Russian Revolution becomes the signal for a proletarian revolution in the West, so that both complement each other, the present Russian common ownership of land may serve as the starting point for a communist development.

Marx and Engels did not study Russian conditions out of academic curiosity. On the contrary, they believed that Russia, once the heartland of backwardness and reaction, had become “the vanguard of revolutionary action in Europe,” so understanding it was a political necessity. This understanding fueled their consistent support for radical populists who took action against the Tsarist regime, and caused them to distance themselves from people who were limited to analysis and commentary. Their approach was motivated, as Marx wrote in another context, by the conviction that “every step of real movement is more important than a dozen programs.”