Some thoughts, somewhat connected.

1. I mentionedthis in a post earlier on. Russian forces can defeat Ukraine but are likely unable to conquer her. An insurgency that has the support of the People can almost always outlast a foreign invader/occupier.I believe RickAir mentioned the exception of using genocide/total destruction. I will grant that exception, but it takes either a level of brutality that would be difficult to command, or a vastly smaller population that i don't think fits Ukraine.

Someone else was dismissive of this likely hood, describing it as being able to only harass.
Consider this: If memory serves (too lazy to check my figures) at our peak we had half a million US soldiers in South Viet Nam plus Korean, Thai, Australian and of course ARVN. We never came close to controlling the countryside. We also never controlled the initiative of contact between ground forces. Westmoreland understood logistics and the use of lethal military power. He never understood Political or Spiritual Power.
Ukraine (though very different geography/climate) is vastly larger than So. Viet Nam.. Is Putin willing to provide an occupying force large enough and long enough to eventually convince Ukrainians that they are willing to once again be Russian vassals? This is the land of The Cossacks. The land of the Khmelnytsky revolt of Fire and Sword that split them from Polish rule. They will use this history of resistance and success to fortify and inspire. To uplift the hearts.

2. We are soon to be in planting season. How much farmland will be under cultivation in Ukraine this year? I assume not much.
How much of the world grain supply comes from Ukraine? It used to be quite a bit. 2022 might be a bleak year.
As a correlation I will add a quote from an introductory speech that Putin gave 21st of October, 2021 at the Valdai Club Conference. Just 5 months ago. "...furthermore, a number of countries and even entire regions are regularly hit by food crises. We will probably discuss this later, but there is every reason to believe that this crisis will become worse in the near future and MAY REACH EXTREME FORMS." (emphasis mine)
You can find this speech and the subsequent interview/discussion on line. It obviously has the limitations/faults of being a translation. If you speak Russian (i do not), it is accompanied by 3:30 Utube video.

3. I was going to comment on the fake news/manipulation of opinions and how we amplify it. Also the schizophrenic political views that are employed to simultaneously hold conflicting history, conclusions and past memory.
Too much for one post.