Well, Putin sees a Ukraine alliance with the West as a threat to Russia, which is certainly is. The US has been trying to encircle Russia, and it is also true that there are a lot of people in Ukraine who would prefer to be in Russia. Ukraine has been horribly corrupt and mismanaged since independence. Russia has controlled Ukraine for at least a thousand years, since medieval times. The reality is that a US government would have to be insane to attempt to defeat Russia in Ukraine. It is of no real concern of mine who controls Crimea or Donetsk.
Years ago, Betty Bumpers, the wife of the Arkansas senator, had a pen pal effort, and I corresponded with Lyudmila Derkatch, a HS English teacher in the Eastern Ukrainian city then known as Kommunarsk, and now known as Alchevsk. She said her students were interested in American cars, so I mailed her a book filled with color pictures of all sorts of flashy cars from the 50's and 60's. We wrote several letters, and she said she was going to send me some books and photos as well, but never did. This was in the 1980's, and she was several years older than me, so there is a good chance she died. She mentioned how proud she was of Crimea, but told me that she had never actually been there. This is in the currently disputed territory, an industrial area known as the Donbass.
She said she had a Moskvitch (a popular Russian car) and a dasha in a forest not far from Kommunarsk, where she had seen bears and deer.