IMVHO are very wrong questions, like aiming at flame pinnacles instead of the base: why "putin" invade Ukraine? Perhaps because since 2014 (and so probably years before) USA formed and armed nazi militias there? Oh, of course putin is a dictator not much different than nazi, but of course he want to protect his territory.
Do remember a thing since WWII end there was Yalta agreements, violated from day zero by NATO with the air bridge to Berlin, with proposed ops like "Operation Unthinkable" and "Operation Dropshot", with Solidarność etc and those activities are still very active around Russians borders.
So how to stop the war? Well, arresting the "western puppets governments" in the eastern Europe playing the neutrality card as Finland, Sweden etc have done in the past. That immediately stop a war who advantage FAR more China, USA and UK than Russia or EU. Just try to study history and geopolitics a bit: China? They get a far more dependent Russia witch means far more cheap natural resources, far bigger hi-tech military gear, probably enough with the Chinese industrial system to being able to counter the USA in few years. For USA and UK? Their government are not hyper-contested anymore, they are not at the brink of a civil war anymore because of an outside war. Any move wanted for the Green New Deal, like skyrocketing oil and gas prices, is now justified and so on. Russia? The war is needed by them to secure their borders but it's costly. EU? Being against our own major supplier of natural resources is simply suicidal.