Two things. a) Putin's actions in Ukraine (and who knows where else) have ideological justifications similar to China's justifications of their actions in Xinjiang and Tibet.

But also, the lines used by both regimes bear aesthetic resemblance to "anti-colonialist" and "anti-imperialist" narratives propagated by both the Stalinist and Maoist regimes in the past. Lots of "we're counteracting western aggression" [somewhat questionable here, Russia has never been under explicit military threat in this century] and "but the west does it too" [whataboutism, a diversion tactic]

They were hypocritical arguments back in the Soviet era, with the way the Soviets treated Poland or Afghanistan, etc. but are way more threadbare now, hollowed of any "substance" at all.

So I don't know how much of what is going on in China in regards to this is actually based on any geo-political strategy or how much of it is just reflexive fall-back to classic Maoist views of the west, a position against western imperialism.

Like, we want to see some global strategy here, but it's also quite likely that the people at the heads of these regimes are much more incompetent than we give them credit for, and playing a game infused with ideological grudges which are only partially understood in the west.

Clearly what is long-term good for China is continued peaceful trade with the west. Yes, there's tension around the basis of that, and how it is formulated. And "the west" certainly has its own aggressive colonialist and imperialist dominance which China feels compelled to counteract. But it seems to me there is no reason for China to toss the table over and stir up this level of chaos. It feels extremely ideological.

Putin's rambling speech before the invasion -- justifying it -- referenced old debates within the Soviet past... he directly referenced and attacked Lenin and Lenin's positions (and Trotsky's -- a Ukrainian Jew) on the "national question" and national self-determination. Essentially from his POV Ukraine "only existed" because of the early Bolshevik positions on ethnicities etc.

Classical Leninism, pre-Stalin, was concerned with granting federal independence to various Soviet ethnicities, to explicitly take apart Tsarist imperialism, and establish what they saw as a socialist federalism and this went along with an internationalist focus as well, as they hoped their revolution would spread to the west (and it did, sort of, in Germany and Hungary, but fizzled out.)

After the failure of revolution in the west, and after Lenin died, Stalin came to power, brutally purged most of the old Bolsheviks, and instituted a kind of revanchist policy and restored major aspects of the old Tsarist pre-revolutionary Russian bureaucracy and internal policies. He paid some lip service to Lenin's position on the national question but basically committed internal genocide (and forced relocations) on various minority populations in the USSR, and was responsible for millions of deaths in Ukraine. Sort of ironic given he himself was of a minority ethnicity (Georgian) origin.

Anyways, in Putin's speech he said explicitly that Lenin's position on national self-determination was incompatible with a functional state. And he's right. Lenin's position was explicitly against the kind of (authoritarian, Russo-supremacist) state Putin wants, and Stalin wanted, which is why Stalin had to murder all the old guard Bolsheviks while committing genocide against Ukrainians (and others) and Putin has to invade Ukraine and god knows who else next. Their image/fantasy of what Russia is or has to be, requires it. And given China's behaviour in Tibet and Xinjiang, they have similar perspectives.