You have to look at the likelihood of these problems leading to a violent regime change. The reasons why Xi is much more safe than Putin are structural.

Xi controls the politburo standing committee which is packed with loyalists. Loyalty is centralized and based in ideology. The state, functions as the embodiment of Xi’s ideology. There exists no independent power base. Military or otherwise. And this is the most important reason Xi is pretty safe. China’s elite is deeply invested in the system (wealth, family, careers). They lose everything if the party fractures. So the choice for those who don’t like Xi is between Xi and chaos.

In Russia power is split. Between oligarchs, security services, military and regional elites. All of which represent a threat to Putin’s power. Just look at Prigozhin’s mutiny: armed forces hesitated, elites stood back to see who would win, system didn’t close ranks. Institutions are hollowed out with no clear loyalty. And loyalty itself is highly transactional. Never ideological. There is zero cohesion in the elite. Zero.

It is also important to look at the histories of China and Russia respectively. In Russia power has _always_ been fragmented. Even under Stalin, considerable power was in the hands of criminal organizations and the communist regime had to co-exist with the criminal classes. In fact, during Stalin, they actually got a worse as the harsh political climate forced them to become more resilient.