It was two of the better armed Ukrainian strike brigades against literal conscripts. And I am not saying that as a perjorative, it's just that is how you run defense-in-depth when you have a 'border front' as long as Russia's. Conscripts are expected to retreat or surrender until military assets actually equipped to deal with whatever is happening can be mustered and the situation is contained. Unlike with the Donbas, there hasn't been 6-8 years of entrenchment going on so there is no reason to expect it to look exactly like the Donbas front.

The Ukrainians appear to be basically doing a really heavily armed raid, which is unlikely to do any real permanent damage, unless they can start fucking the natural gas pipelines in Sudzha to the Czech and Hungary, but is meant to fuck with Russian morale and increase Ukrainian morale. Which idk how it has worked, because it is not like there is any accurate polling on attitudes outside of the war watchers.

I don't think anybody 'fucked up', it's just another occurrence in the conflict.

No the mission was to take the NPP and they failed and got routed. They never even got close to their objective. They sacrificed all of their equipment and best troops for a 2 week long PR victory and an acceleration of the ongoing collapse of the Donbas front. This was a very risky all-or-nothing hail mary and it failed before even reaching like 15% of its goal. It will result in thousands of dead Ukrainians for absolutely no gain whatsoever

Most of the fighting in Donbass is in or around the Ukrainian defenses and trenches they've built since 2014. Likewise Ukraine failed their offensive last year because the Russians built their own defenses.

This is the biggest reason the war seems to be slow, and the fact there is way too much urban fighting. Almost every little village needs to be completely destroyed. The open fields both sides capture are easy exactly because because they're a trap for massive artillery and drone attacks.