The end of Putin is a bit strong. Kim Il-sung invaded South Korea in 1950. The invasion destroyed his army and required Chinese intervention to fight the US to a draw. He lived to a ripe old age, killing any internal rivals who got in his way. And Kim was a Russian puppet selected for his subservience, not his ability.
Then there’s the case of Saddam Hussein, who started two failed land grabs, against Iran and Kuwait. He survived in office until the US invaded Iraq. And even then, he remained in charge of Baathist/Islamist insurgents until the US pulled him out of his hiding place.
No one handed Putin his job. He clawed his way to power. He knows a thing or two about how to appoint men he can trust with his life to key positions and keep them from conspiring against him individually or in collusion with each other. If he loses and withdraws from Ukraine, he will likely continue to rule Russia until the end of his natural life just like his North Korean counterpart.
Look at Maduro and Gaddafi. They tanked their countries’ economies despite tremendous amounts of oil resources. Gaddafi invaded Chad, lost and took huge losses in men and equipment. It took foreign intervention/invasion to remove one of them. Look at Mugabe. Only personal infirmity in the form of senility removed him from office.
Hillary and Obama showed him! She went one further and broke Libya into pieces, and started a civil war which is still going on.