Putin started the war. Zelensky did not. Russia invaded Ukraine - not the other way around.
Zelensky started the war when he allied with NATO after being assigned power by Western forces after a violent terrorist coup. That was an act of war against Russia. Wars don’t just start when the first shot is fired. That is naive. Study military history and theory. When Athens brought Megara into the Delian league - the predecessor of the Athenian empire - they knew they were provoking war with Sparta. They made it look like a defensive alliance knowing Sparta’s Pelopponesian allies would insist on attacking Megara, drawing in Sparta and making Sparta look like the aggressor.
This is a very old and well known technique used by many empires - including the American one. Heck, the deep state knew damn well that having an obviously fake 2020 election would bring a violent backlash and thus make Trump supporters look like the aggressors. But they struck the first blow.
The American empire provoked this terrible war. Russia fired the first shot . Both are to blame.