US Secretary of State Blinken says that if China were to provide 'material' lethal suport for Russian agression, then it will be a 'serious' problem for 'our' countries.
It's not clear if he's talking about the G20 or G7.
You wonder how far the US and others would be willing to go to sanction China or if it would be token moves. For China, that cost might be something they want to weigh against testing some of their weapons in war, or strengthening access to Russian resources.