> Then again, if Chechnya showed anything, it is that Russia can play long occupation and 'win'.

You can't compare Ukraine with Chechnya. Also Russian soldiers are much more hesitant to attack Ukrainians, the plan as I see it was to scare them to surrender, but Ukrainians weren't scared so what could follow might be a horror for humanity to behold if it continues for a long time because resentment builds up we might see some terrible atrocities of war.