The Ukrainians destroyed the elite VDK paratroopers who attempted to seize the airport outside of Kyiv. It's still too early to know what happened but perhaps Zelensky was leading the Russians into thinking that Ukraine was unprepared and look at what happened during the battle of Kyiv which was a colossal defeat for the Russians. If the Russians thought that the Ukrainians were prepared, they might have attacked Ukraine differently. More artillery and air strikes which are Russian strengths.
The shock of that transport being shot down and over 160 elite paratroopers suddenly killed had a huge detrimental effect on the Russia’s initial offensive. After that disaster their attack on Kiev was thrown into disarray. Any hopes of ending the war in a week were over when they were unable to capture Kiev. Morale plummeted and they simply did not plan logistically for a long war.
Zelensky didn’t have the political strength or gumption to do that.
Russian troops just failed. Badly
No perhaps about it. Zelensky led Russia on with feigned ignorance.