The first is a video of a Russian helicopter being shot down in Ukraine. The second is a video of a Russian helicopter in Ukrainian airspace. You can see
The Ukrainian army is pretty much ineffectual, but they have had their moments. Portable anti-aircraft missiles are what kicked the Soviets out of Afghanistan many year ago. In my own opinion, this is the only strategy that makes sense, flood the area with anti-air and anti-tank weapons and train a few thousand Ukrainians in asymmetric warfare.
By the way, if you want to see more detail of the power of a Russian combat helicopter check out this Rambo clip. The Ka-52 is a massively upgraded version of the what is portrayed in the Rambo movie.