This NYT article is the source, I think
“That is not the question,” Mr. Barroso said Mr. Putin told him. He continued, referring to the Ukrainian capital, “But if I wanted to, I could take Kiev in two weeks.”
So Barroso said Putin said this (in 2014)
Yeah just to be clear, I'm not saying he said this, I just did some philological excavation.
All in all, if Russia gave it her 100% military power even excluding nukes they could've ended it in 2 weeks even in 2022, simply by doing decapitation strikes and bombing every bridge airport and power station