The there states that created the USSR (the Russian SSR, the Ukrainian SSR and the Belorussian SSR) abolished the treaty that established the USSR.
So according to Chinese logic, the Belovezha Accords confirm that the establishment of the USSR is a “historical document” that has been consigned to the dustbin.
And any nation state admitted to the UN since is de facto and de jure a recognised independent nation state.
How does any of what Macron or Xi are saying affect the Taiwan situation?