It seems like quite a lot of people think that the current war in Ukraine is entirely down to Putin, and if Putin dies / is assassinated / is replaced in a coup etc, then the war will end. Examples:
WASHINGTON -- South Carolina Sen. Lindsey Graham is facing intense pushback from all corners of Washington after calling for the Russian people to end the Ukraine war by assassinating President Vladimir Putin.
The only way out of this crisis is to make Putin’s failure in Ukraine so disastrous for Russia and its genuine interests that his own elite will have no choice but to remove him.
Some protests say "Stop Putin" instead of "Stop Russia".
The implication is that 1) the current war is entirely because of Putin, and Putin only; and 2) if Putin loses power somehow then the war will cease because his successor will not continue the war.
How do we know that Russian foreign policy will change (and by how much) should Putin lose power?
Related: Why do news articles often refer to the leader as opposed to the country? However, the current anti-Putin (but not anti-Russia) news seems more precisely targeted on Putin than the answer to that question would indicate.