If the USA had been punished in the same manner for its atrocities in Iraq and Afghanistan, would we have had the rest of the disaster unfold?
And we see the end result of this line of thought in Gaza, where literally millions of human beings lives have been irreversibly damaged for generations, because someone decided to punish their enemy at massive scales. And as we can see in the case of Gaza, this is no guarantee of peace, whatsoever. This line of thought has led to genocide and ethnic cleansing at massive scales.
And, it simply does not work. Period. There are generations of new terrorists who want vengeance in the Gaza/Israel war, just as vehemently as Americans do, for the Ukraine/Russia war. These children will only be converted back to peace-makers if their lives are _improved_ by the peace plan, not made worse, and there is a long, long road ahead in both wars, for all parties, to attain that condition.
At some point, making peace means putting aside any aggression-based arguments and just getting on with the program to bring both sides together, to stop the fighting and start the economic unity required to keep things peaceful.
This peace plan seems like an attempt to do just that, so it should be supported. After all, it does contain triggers that will re-ignite the war machine again - and, it could be argued that should those triggers be activated, the war would be more justifiable to the world community, and those who seek a wider, escalated war against Russia, will get their fulfilment if this plan is betrayed. This peace plan would be the first step towards greater forms of punishment - but it works for both sides. If Putin violates the agreement - Russia comes under attack by the entire world. If Ukraine's leadership violates the agreement, Russia gets cart blanche to continue its dismantling of the Ukrainian state. Therefore, the peace-makers must have the reins in lieu of the warmongers, as of now.
(Disclaimer: I've read the peace plan, have Ukrainian and Russian friends in my circles who are veterans from the conflict, and their opinion is: yes, it is far past the point where the aggressive warrior narcissists need to be ignored and statesmen and diplomats need to work harder to re-establish peace between the two nations. I personally feel that this plan has to proceed, or else the entire world is going to see the conflict expand to our own borders. This means the hyper-actualisation of warrior narcissism needs to stop, and civilisation-building economic tools need to be better applied - by all parties - to ensure the region is rebuilt again. Trust must be restored through economic unity, first and foremost - that is what this plan aims to achieve.)