> They were humiliated, were dragged to Versailles to sign an armistice treaty and had to pay an insane reparation amount.
Technically the armistice is in Compiègne, the peace treaty is in Versailles (as revenge for the proclamation of the German empire there after the Franco-Prussian war), but yes, however
> Germany definitely understood they lost.
This is false. Germans were getting glorious victories propaganda up until Ludendorff said they can't win, and threw the hot potato at the Kaiser and a civilian government was formed to seek a peace. So from a citizen's perspective, there were privations but they were winning until suddenly there's a civilian government, communist rebels and we have surrendered (to be later humiliated). Germany wasn't occupied. The German people didn't understand they lost, really, and why. Hence Ludendorff's stab in the back myth and nationalism proliferated.
> Russia army has been mostly destroyed. Its economy is faltering. Its ability to wage war is greatly reduced. Its standing on the international scene forever diminished.
But Russians don't know that because they're being fed propaganda to the opposite effect. So if today Putin declares withdrawal, Russian people won't know what happened and why, so we'll be back at it in a few years time.
The point isn't to make Russia suffer for the humiliation, but Russians need to understand they've lost and all the horrors they've inflicted while losing. And yes, they should pay for it.