Even if they take Kyiv and kill Zelenskky etc. There is no way the Ukrainian army will stop and nor will the people accept whatever puppet Putin installs and neither can the Russian Army subdue the whole Ukranian population.
In two weeks, the Russians have lost more troops than the US lost during 8 years in Iraq. Its not sustainable.
The thing that struck me, is where it describes territorial auxiliaries who are able to position themselves in ambush situations and pick-off columns with the weapons they have received (from the likes of UK).
Even if the Ukrainian professional army are in retreat or are outgunned in a particular vicinity, the travelling Russian vehicles are vulnerable to assault from armed auxiliaries. Russia would need to scuttle abandoned vehicles to prevent them from falling in to the hands of Ukrainian forces.
Whatever the Ukrainians have done regarding training territorials or having received training from NATO forces for their own professional army - I would have expected Russia to have had intelligence of such and to calculate the risk. This seems to be lacking.
Another issue that has come to light is the use of Russian conscripts as opposed to their professional army. Surely conscripts should have been in the rear? I may sound like an armchair general but there you have it.
On top of the needless casualties on both sides, the thing that pisses me off is that Putin has inestimably weakened Russia's position as a counterweight to US. If he has been drawn in to doing this, then you have say he has been outfoxed by the US. When you consider his standing in the wake of Russian intervention in Syria, this could be a huge fall for them. That is not good for the rest of the world, as it simply emboldens the US.