Woah buddy. I don't disagree that Russia is a friend of China, but we are talking about formal treaty alliance, which is very different from just being friends or strategic partners or a circle-jerk.
Looking way too much at history? China does 10X more trade with US than it does with Russia. The reality is, "anti-Americanism" won't result in a Sino-Russian alliance against US or NATO.
Also, I am a Chinese nationalist who distinctly remembers the Tsarist Russian annexation of Qing Chinese territory, imposition of Unequal Treaties, and treating China like an subordinate junior partner during Korean War. If you conveniently brush aside history, you are doomed to repeat the same mistake again in the future. China should never pursue a formal treaty alliance with Russia.
Like you said, there are not eternal friendships, only eternal interests.
During the Qing dynasty, Russia was looking to expand eastward, therefore there were conflicts with China. More significantly, the Soviet Union was trying to establish hegemony over China, hence the split.
Today, Russia is looking westward, more specifically the West poses the greatest existential threat to Russia today. Therefore, China and Russia have aligned interests and many fruitful areas of cooperation.
China has no interest in a formal alliance with Russia, that's just something people who mistake allies for power like to dream about. In reality, allies are not always assets. Allies can often end up as liabilities.
