Orwell left quite clear that after having seen both Nazism and Communism in action, he was staunchly against both forms of totalitarianism.
Indeed! But unlike capitalism, communism does not require totalitarian structures of power. They're actually quite incompatible.
Empires describing themselves as "communist" are more so "state capitalist". The USSR was not a classless society nor a free society so it cannot be called communism: some people had more rights/resources than others (the opposite of "communism").
In marxist views, dictatorship of the pretend-proletariat (red elites are usually not common people) is a capitalist stage of a society advancing towards communism but cannot be considered communism. No pretend-communist country ever outgrew this phase (because power structures do not dissolve by themselves, we have to destroy them).
Orwell was a trotskyist. If we forget just for a minute the lies and inconsistencies of Trotsky (who was a mass-murdering psychopath), trotskyists are libertarian communists. They advocate self-organized cooperation/sharing without central authority (no state). Orwell was therefore close to anarchist ideas. You can feel his admiration for anarchists in his book "Homage to Catalonia".
When the USSR started to overthrow the CNT-led anarchist revolution in Catalunya, anarchists allied with trotskyist militias to fight against fascism and authoritarian communism. They failed of course, because what can you do to survive against two power-hungry emperors (Franco/Staline) who agree to destroy you?
This is not true. The Soviet backed militias forced Anarchists to either fight for their militias or be part of their purge. The Soviets used force to squash the growing (and large) anti-authoritarian sentiment among the Spanish Civil War Republicans.