To revert to an aviation theme, an utter SA failure occurred from the start of this at all levels; perception, comprehension and projection. Similar factors plague the continuation of the war (special cluster F%8#, for naval aviators)
Perception errors stem from prior experience that reinforced mental models that just ain't so. The actions in Chechnya, Syria, and even Ukraine 1.0 gave an overly optimistic expectation of the capabilities of the Russian forces in all areas. The expectation of an OP PLAN "Z"? giving a certain victory in 72 hours would have had Sun Tzu running out getting more quills to write with. The consequences of that assumption continue to reverberate in the field today. Ukraine took the hard lessons of the last 8 years and did something about it, Russia basked in the glory of taking on an unprepared and unexpecting neighbor with a sneak attack worthy of it's own "day that shall live in infamy". When Russia came about again to the rinse & repeat cycle, not too many people were going to cross the party line and advise the Count that there was a bit of a gap between fact and reported status of the might of the realm. Normalization of deviation had also occurred, Russia expected the West to sit back and just cluck away in disdain. The Russians did not factor that NATO, even in a diminished capacity, was able to come together and find common cause in the injustice that had befallen Ukraine, and the inherent risk that an attack on Ukraine imposed on NATO as well. Who knew! Who knew that it was a bad time of the year to undertake combined force actions with mechanized brigades, on ground unsuited for the activity, it had been ever thus.
Comprehension failures abounded in this scratching of the kitty litter. The consequences of the steep learning curve that Russia was given by Ukraine in the first week was lost thereafter, and remains uncorrected to date. Russia had an option to either sort it out or get out, and they chose a third option, rinse & repeat, as it always works better the second time around without correction. Russia managed to dump enough stores and bang on civil population areas and to rape, pillage and murder enough people to be able to suspect that the winning of hearts and minds would be incompatible with the loving kindness shown by the Russian conscript in the field under the quality supervision of the army. That is an own goal, and continues to replicated at every opportunity, stupid is not fixable apparently.
Projection of the consequences of "play it again, Sam" dropped through the floor gratings. Conflict takes 2 to play, and assuming the other side is just going to acquiesce or be less irritated than you would be is a recipe for a lousy day. From day 1, it was evident that there was considerable response to the actions of Russia, and yet the continued ratcheting up of sanctions and of munition supplies to the Ukrainians have Russia bemoaning their fate. This is also the Russian tourist status in the European countries complaining of being less than cordially welcomed, and of the lament that the world's arms being provided to Ukraine are causing hardship and suffering of the poor invader.
The global failure of SA extends to the resolution of the conflict, but adds inertia, resentment, hubris, and self-interest into the mix of making rational choices. The rational options are few, with some variants turning them into a spectrum. Continuing on a bad path hoping for a change in the dice from General Winter or other saviors is tantamount to just hope, and hope is apparently not a rat cunning plan.