If you include American allies and mercenaries, there's plenty of firepower to stop China if it goes belligerent.
The PRC elite do not need a distraction even if 10x more opposition rises up and protests happen. They're not a democracy.
Despite being fairly well equipped, China has shown a lot of restraint when it comes to war.
They recently ended a border conflict with India that they pretty much won. There wasn't really a need for them to back down but war is bad for business and China likes doing business.
Even though Trump woofed a lot, they didn't use the nuclear option, i.e. selling T-bills and T-bonds to tank the US economy. I think they can take a lot more woofing before resorting to war.
I read this article about how it's diplomacy 2.0 at Biden's state department where the new theme is that each nation state is engaged in multifaceted diplomacy. They could be lecturing, denouncing or even sanctioning each other on certain issues such as human rights, even though cooperating deeply in certain others, such as trade. In short, team Biden has all the tools to look tough on China without doing anything and that's what's most likely to happen.