You're taking things out of context. In the first example, Lenin specifically says "bourgeois reformist assertion", he's talking of monopoly in the context of a bourgeois state, not in a worker's state. He understands that for as long as a strong bourgeoisie exists, not even a state monopoly can be considered socialist, because the state is in fact controlled by the bourgeoisie.

That was until after the October revolution

Wow, so you're telling me that, when confronted with real situations and material conditions, the opinions of someone can change? Baffling.

This is around the time he stripped the soviets of their power and disenfranchised the workers in favour of a central state that alienated them from control over the means of production

Good luck fighting a civil war in which you get invaded by 14 other world powers for the sin of being a communist, while your industry is disorganized and not centralized towards the war-effort. Give as an answer as to how to fight and win such a war, maybe the entire communist part just didn't think hard enough? Or will you say that the people who spent most of their adult life in jail or exile for organizing workers and distributing communist newspapers during Tsarism were ackchually just power-hungry tyrants?

And now tankies are distancing themselves

Wait, so tankies are actually against centralized economic planning? Strawman

an analysis of what happened shows that the USSR liberalised quickly

"liberalism is when centrally-planned economy". Seriously, do you know what "liberalism" means?

You know your REAL problem with the Bolsheviks? That they won. The problem YOU have with Bolsheviks, is that they had to face real historical and material problems, and big ones, and therefore had to make tough decisions. You claim to know better than the people of the time that spent their literal lives in jail or exile prior to the revolution, studying and theorizing and discussing about communism in real life, risking their lives in organizing the workers and in fighting against Tsarism, and you know why? Because the ONLY socialists that supposed "leftists" like you will support, are the leftists who failed. You'll support Salvador Allende because he didn't face the real conditions of his time and didn't apply the necessary policy to fight the advance of fascism. You'll support the anarchists in the Spanish Second Republic because they failed to fight against fascism and, because of rejecting taking power, they didn't have to apply harsh policy to fight reactionarism. But you won't ever support actual socialists who DID understand the dangers of fascism and of capitalist counter-revolution, and actually did something about it, because as soon as they apply their ideology to real-world conditions, they're not perfect anymore. Because they ACTUALLY were a threat to the system, and so the propaganda will paint them as intolerable autocrats, and you'll swallow that propaganda whole and share the same views of socialists than fucking Zbigniew Brzezinsky.