Precisely this situation is unfolding in Myanmar right now. The junta is so weakened that they have no choice but to turn to China. Chinese troops will be in Myanmar soon to protect Chinese infrastructure investment:
https://www.rfa.org/english/opinions/2024/11/23/opinion-myan...
https://theconversation.com/chinese-security-companies-are-p...
https://www.voanews.com/a/china-backed-election-raises-fears...
If Russia decides to have a civil war, China will do the same in Russia.