There’s an easy way to end this war: either kill Putin or have Putin resign.
Literally not a fallacy, your reasoning hinges on Great Man Theory. The two most popular parties (the second being the communist party) both mainly support the war and the assassination of a sitting President would not, in fact, make the country more dove-ish. It’s a cartoon view of the conflict that the war spawned from Putin’s brain and is his personal pet project that he is subjecting the rest of Russia to.
Because it takes away the puppet Russia has been building and nurturing this whole time.