I'm not sure where did you got that Russian invasion become surprise for Ukraine, NATO and West. IIRC, few days before inavsion, USA intelligence warned that inavsion can begin at any moment, on 23th February state of emergency started in Ukraine. Though, Ukraine admitted that they didn't expected invasion in North, from Belarus side.
It doesn't matter how well Ukraine prepared for a Russian invasion if it missed a surprise blow. Although TwitchySeal believes that Ukraine won near Kyiv and kicked Russia's ass there, putting it to flight. This feature of Ukrainian propaganda does not surprise me; it even declared the defeat of the Armed Forces of Ukraine in Mariupol as a victory.
And I'm not sure why you're saying about too small forces, when there was close ti 200k troops near to Ukrainian border.
200,000 soldiers is dramatically small to start an operation; according to NATO intelligence estimates, the minimum number required to control only the eastern part of Ukraine is 400,000 soldiers. Russia began the operation with half the resources in terms of manpower, dispersed in addition to the East, also in the North and South. I think that's why NATO considered Putin's statements a bluff, NATO intelligence had accurate data, but made incorrect conclusions from them.
So, Mariupol's infrastructure isn't good after all? But I used it just as most obvious example, there is lot of smaller cities with huge damage like Severodonetsk or Borodyanka.
Mariupol suffered significantly in urban battles, it's true. The Azovstal plant cannot be restored, blast furnaces cannot be turned off and turned back on like a gas burner - this is a continuous cycle enterprise. Everything else will be restored. Mariupol has a very important strategic importance in this operation for a number of reasons, so I think the victims were not in vain.
And this ''civilian war'' was started by Russia 8 years ago. And what is genocide of Russian speaking Donbass population is still big mistery for me.
You have an interesting interpretation of historical events, but I do not agree with it.