Best case for China is that Russia loses the war in Ukraine and a weakened Russia becomes a Chinese satrapy. There are Russian natural resources China needs.

Now, obvious support for Russia would make even more trouble in the US/China relationship. As it is, I've seen at least rumors that the US ban on exports to China has expanded from high end chips, chip-fab gear for high and medium end chips to include airframes (US reaction to the 'show' China put on after Pelosi visited Taiwan). China's economy is not dependent on the US, but it would be quite a blow to lose it (and they're spectacularly over-leveraged as it is). Ejection from the MFN group has Bretton Woods Accords and maritime insurance implications as well.

Also: if you live in the US and have wondered why the hell we have such a ginormous military budget, it comes down to a lesson the US took from WWII and having to postpone the Pacific war while the European one was on. The US military is budgeted and built for two simultaneous conflicts and has been since Truman. I think it's an absurd overreaction that's been sucking us into local quagmires around the globe since then, but there it is.