> In other words, if you tried to "do a communism", you'd either be carpet bombed (or more likely have a fascist coup funded against you) by the US, or you'd be made an offer you can't refuse by the Soviet Union. The inevitable outcome of this was that the only "communist experiments" that were able to grow in that era of history were ones that instantly aligned with the Soviet Union or that were sufficiently non-threatening and irrelevant to both sides (and thus likely never showed up on your radar).
This isn't true, and many communist countries were openly hostile to the USSR. Yugoslavia went it's own way, China split with the USSR and had a war, Albania sided with China against the USSR, the Khmer Rouge were hostile to the USSR, North Korea tried to position themselves between the USSR and China. Even many countries that were aligned with the USSR weren't controlled by them (for example, Vietnam and Laos).
Saying "this isn't true" and then listing a bunch of countries which either explicitly sided with China, were aligned with USSR "but not controlled by them" or that literally have Wikipedia articles called "$Country-Soviet split" is a bit silly. I never said that they were vassal states. I said they instantly aligned with the Soviet Union or had to be irrelevant to both sides. Albania, China and Yugoslavia are "counter-examples" only in that they were initially aligned with the Soviet Union but then deviated from it.
The Sino-Soviet split pretty much occurred because the Soviet Union itself deviated from Stalinism and Mao didn't like that. China only got away with that because like the USSR it was extremely large and powerful. It literally split off to become a third superpower and its ideology was functionally indistinguishable from the Soviet Union with regard to its ability to achieve the supposed outcome of communism and its insistence on giving all power to the state in the meantime.
Albania initially sided with Mao in order to split from the Soviet Union because much like Mao, Hoxha disagreed with post-Stalinist reviosionism in the USSR. Its split with China in turn was the result of China's embrace of liberal market reforms under Deng, i.e. another round of revisionism.
Yugoslavia only survived its break with the Soviet Union because it (like China post-Mao) opened itself up to the US. However Yugoslavia's "communist" origins are directly tied to the Soviet Union, it's still downstream from Marxism-Leninism.
The Khmer Rouge were also downstream of Marxism-Leninism and directly funded by China. Vietnam is probably the most ridiculous example you could have thought of given that the entire Vietnam War was a thing (and Ho Chi Minh Thought is also of course downstream from Marxism-Leninism). Likewise North Korea with the Korea War and it nowadays pretty much only existing at the behest of China (its only serious ally).
I'm not sure what you were going for but if you wanted to disprove "if you tried to 'do a communism' you had to align with the Soviet Union or be bombed by the United States" the only thing you've accomplished is adding the nuance that you had to either align with the Soviet Union or, post Sino-Soviet split, China. The point remains that unless you were somehow compatible with Marxist-Leninism in one of its many forms, you were on your own against the United States and its economic geopolitical interests.
This isn't true, and many communist countries were openly hostile to the USSR. Yugoslavia went it's own way, China split with the USSR and had a war, Albania sided with China against the USSR, the Khmer Rouge were hostile to the USSR, North Korea tried to position themselves between the USSR and China. Even many countries that were aligned with the USSR weren't controlled by them (for example, Vietnam and Laos).