If China can become a quasi-ally with US to counter the Soviet Union, then it's not outside the realm of possibility that "Reverse Nixon" is also possible: that Russia can be an quasi-ally with US to counter China. I don't see how Russia, a former Superpower, can accept or tolerate to be subordinate junior partner to China, particularly an alien civilization with no shared language, culture, or even ideology like Communism (like old times). You have to have more than just "Anti-Americanism" to form the basis of a long-term alliance, the Sino-Soviet Split demonstrated this.
I disagree. Even if Russia changes president and wants to build better ties with the West, China is still an important partner. Russia will want to take advantage of both. Not surrender to either side. The West will always try to bend Russia to its will. The West have been doing this for the last 100 years, they will continue to do so.
China OTOH never treated Russia like a junior partner. China didn't demand Russia to become Communist again. China didn't try to pull Russia's Eastern neighbours into an alliance to confront Russia. The SCO also includes Russia, and Russia can also keep the CSTO. There are no sides to choose for Central Asian nations. There is no hostile competition to recruit allies in Central Asia and Eastern Europe. No matter how alien China is to Russia, China was historically not an existential threat. All the bloodiest wars in modern Russian history were inflicted by the West and Japan.
Boris Yeltsin, the most pro-West Russian leader in modern history was still quite friendly to China. Although Gorbachev started to warm to China. When Yeltsin took over, he still continued the warming relationship to China. Russia and China had their problems in the past, but both have learned their lessons. Russia learned to not conduct imperialism on China. And China learned that excessive Maoism is not good for foreign policy.
Just like how the Sino-Soviet split happened. It wasn't ideology or culture that defined China - Russian relations. It was mutual trust. China and Russia learned it the hard way that undermining your closest neighbours for the benefit of outside powers is a bad idea. Both were played by the West against each other, and both got burned by the West. Now, that both had awakened to the manipulations of the West, there is no going back. Mutual trust between Russia and China has never been higher in both of their histories.
Russia had fully embraced the West before, during Yeltsin's reign. The next thing the West did was to vacuum out the economy of Russia, move NATO eastwards, and encouraged the further disintegration of the Russian state. Russia may want to get closer to the West in the future, it is their sovereign right to do so. But it won't do so at the expense of its relations to China. Russia will never trust the West like Yeltsin ever again.