How much would China endure? A lot... because they know the reason we are so desperate to get a cease fire in the Ukraine isn’t humanitarian, it is for one reason only... so we can pivot and target them.
China is smart enough to know that their tolerance for pain exceeds ours. And that Russia being able to stop the DC/London axis, is good for China also.
And China is not a democrat problem. Republicans want the China project to keep going also.
I wouldn’t concede the pain question so easily. The Chinese leadership don’t care; sure. However, protests and unrest in China may happen quickly and though it may not end the regime their response could also change dynamics. You may end up being correct but I don’t think they are without risk.