Holly shit, what a mess.
Lets point some things out:
1. Putin was so sure that this war will be a piece of cake that he didn't prepare for a war longer than couple of weeks.
2. Also, the russian invasion army was so fuckin small - what they was thinking, that they will beat up a heavily militarized country with 40 000 000 population with circa 200 000 troops? Really?
3. Also, Russians are not learning on own mistakes - as usual, they are trying to take a city (full of light infantry with anti-tank personal gun) only with unsupported tanks. This shit din't work in Grozny '94 (funfact: many of Ukrainian far-right fanatics from UNA-UNSO was fighting side by side with muslim extremists in that battle), and will not work in ANY city where is placed few guys with light rockets.
They also didn't think that west will support Ukraine in any way. NATO probably is secretly threating Russia with using force if any russian land units will be present in west Ukraine. And probably Russians have this on mind - well, they prepared pretty big force in Belarus with the aim to go on west Ukraine on general direction of Lviv, and from some reasons they didn't move on that part of border. Guess why?
Also, probably NATO will start using force in some way (e.g. no-fly zone west of Dnieper) if the war will not be ended by ceasefire in next week.
And yes, before war I was beting that Putin will not attack Ukraine - because as we see Russia have not enough force to conduct this war or to win it. Idea of getting 200 000 soldiers with shitty tanks and going into Ukraine was so stupid, and I was thinking that Russians are smart enough to see that and not starting a fire in their own house. Well... last tsar was also pretty stupid, and started war with no chance for victory. Perhaps Putin is more like Nicholas II.