I don't worry a lot about a Russian-Chinese alliance. Neither can help the other militarily. And in my view only Russia really needs a Russia-China non-aggression pact.
I think this assessment about an alliance between Russia and China is right:
A military alliance is similarly problematic. Neither Russia nor China can support the other’s strategic needs. The primary threat to China is naval. Russia’s naval capacity is limited, and its major Asian port, Vladivostok, requires passage through maritime routes that are controlled by Japan and the United States. Russia would be contained by the same coalition threatening China. The threats to Russia are primarily terrestrial. China’s ability to send forces to areas of Russian concern is limited, and Russia has no pressing need for additional ground troops. There are areas in which one could help the other, such as military hardware or cyberwarfare, but that isn’t a real alliance.
Could a Russo-Chinese alliance launch a naval assault in the east and a ground attack in the west simultaneously? Perhaps. But doing so, while politically shocking, would not weaken either front because it would be engaging naval forces not needed in the west and ground forces not needed in the east. It may also fail. If it succeeded, it would trigger existential (nuclear) choices or create unshakeable anti-Russia and anti-China alliances.
I think Russia needs China pointed out to sea at America and our allies in East Asia.
In order to protect Russia's 19th century conquests from Chinese land claims.
And while Russia bought five more years of non-aggression, is that enough time from Moscow's perspective to pivot to Asia?
