Personally, I think people exaggerate the “revisionist” ideology involved in the sino-soviet split as the only major factor at play, and they miss the other huge factor at play. China just came out of its Century of Humiliation. There was naturally an incredibly strong paranoia that they would get imperialized again. The Soviets did not help assuage these fears when they started to become heavily influential in China’s direct bordering neighbors; Korea, Mongolia, Vietnam, and later Afghanistan.
If the sino-soviet split was purely about Mao trying to fight Soviet “revisionism,” why did it continue after Mao’s administration ended? It’s not like the Deng administration adhered to the Stalin Model at all, yet the split remained. Well, actually relations did start to finally normalize in the later 1980s culminating in the Sino-Soviet Summit. The reason was that Gorbachev had agreed to some of China’s long-standing demands: to withdraw troops from places like Afghanistan and Mongolia.
You see, Mongolia is on China’s northern border, Vietnam+Cambodia is on China’s southern border, and Afghanistan is on China’s western border. (The eastern border is just the sea.) In all those three land borders, there was huge Soviet presence, so they were basically surrounded by the Soviet military and given their history, they were naturally paranoid of any big country surrounding them and viewed it as an existential threat.
China has a very long history of constantly breaking apart and reforming again in new eras. This process is very messy, a lot of violence and, more importantly, border changes. Many times in history that his led to Vietnam being invaded by China. So, naturally, the Vietnamese also are a bit fearful of China and do not have the best relationship.
Vietnam sought very close relations with the Soviets as a way to offset this, to the point of having a Soviet military presence in Vietnam. The Chinese did not like a foreign country having a military presence in a bordering power that they have mixed relations with, so they, under Mao’s administration, tried to ally closely with Cambodia to offset this.
However, Cambodia decided to attack Vietnam and then lost the war they started. As the losers, the Vietnamese got to replace their government, and thus Cambodia became a borderline Vietnamese puppet state, which increased tensions between China and the Soviets even more since this meant by proxy more Soviet influence in the region also extended to Cambodia. Just look at what the Cambodia’s People Party did after the USSR fell apart. They immediately flip-flopped from a Marxist-Leninist party to a right-wing monarchist party basically overnight. Unlike the Vietnamese, the Cambodian leadership didn’t really actually embrace Marxism-Leninism and were largely just propped up by a foreign power.
That’s why the Deng administration attacked Vietnam, not with the intent of actually conquering it but as a show of force to say basically “we’re still the boss of this region” since the fall of Cambodia meant a fall of Chinese influence in Cambodia and its replacement by Vietnamese influence and, by proxy, Soviet influence.
A lot of the conflict was realpolitik of China very untrustworthy of any other big powers due to the Century of Humiliation and viewing the Soviets as an expansionist power and thus an existential threat to China, and so relations did not really start normalizing until the Soviets agreed to reduce their influence in the region. But by that point the USSR was already falling apart.
Ideology did play a role but it was moreso tangential and not the fundamental reason for the split. Given China’s history, they were already very uneasy about a major power like the Soviets having so much influence in the region, and Mao viewed de-Stalinization as a betrayal, and so ideology played a role as a tipping point. But you then have to ask the question, why were the relations so fragile in the first place that de-Stalinization was enough to cause friendly powers to suddenly become incredibly hostile towards each other? It’s because the relations were already built upon sand, given China’s historical situation combined with the Soviet’s desire to expand their influence.
Maybe. In one Chinese textbook I read, the author routinely criticized the USSR’s policies in the way it enforced socialism in other countries, usually enforcing a vision of socialism of specifically Russian origin and oppressing local socialist movements who wanted to tailor socialism to their own material conditions. The Chinese did not like this kind of domination and were fearful of it because they did not want to become a Soviet puppet. I think the Soviets could have potentially made decisions to show it was less interested in domination, but I also do think it is fair to say the Chinese could have been less paranoid as well. It’s hard for me to specifically pick a side because both Mao and Khrushchev did/said some unhinged things at times.