What worries me is that China is making friendly overtures to Russia. If they really get involved in this mess it will become a thousand times worse.
...A thousand times worse for the Ukrainians, maybe, but honestly, most of the rest of the world would benefit.
If the Chinese want to send their military across half of Asia to fight in unfamiliar terrain against battle-hardened veterans with superior equipment and training, well...
The only major restraint on how much war material the US is handing over to Ukraine, is the need to be ready to fight China. Make it clear that supporting the Ukrainians is a twofer, and you can wear out the bear
and the dragon?
F-16s would enter Ukrainian service in months, the Abrams would start arriving by the hundred instead of dozens, and we'd probably ramp up to full wartime production on all munitions.
The most likely result would be that the PLA proves just as much a paper tiger as the Russian military. You'd probably also see more Taiwanese volunteers, looking to gain direct intel on how the PLA would fight, and kill a few commies while they can.
I honestly don't see it changing the outcome of the war in Russia's favor. If anything, Europe would also be doubling down on how much support they send, and this just ends badly for the Chinese.