Putin thought the war was only going to be for a few days - according to research by the think tank RUSI, when Vladimir Putin began his invasion, he expected to take control of Ukraine within 10 days https://www.iwm.org.uk/history/how-Putin-lost-in-10-days. He couldn't pull out of the war subsequently in fear of losing control and face. Xi is an idiot, but even he can see his potential downfall, given Russia's failure.