US government has a policy that the nations in the Western hemisphere can't have a foreign policy that can threaten America's designs in this hemisphere. A clear example we can cite is the Cuban missile crisis where US was threatening to trigger a nuclear conflict if those nuclear weapons weren't removed from Cuba. Keep in mind Cuba is a sovereign country.
Russia has similar policy where it doesn't want NATO at its borders, meaning nations that border them shouldn't threaten the security of Russia. So when Zelensky puppet decided to be Victoria Nuland's poodle and called for NATO membership, and when Biden refused to rule out Ukraine's membership in NATO, and when the NAZIS in Ukraine declared a genocidal war on Russian-speaking communities in the Donbas region, Russia was given no choice but to act. Bottom line what is good for the goose is good for the gander!
The whole reason why you saw those Ukrainian forces in civilian cars is because they were escaping the cauldron that was about to be placed on them.
Luhansk People's Republic is almost liberated and the rest of Donbass is about to fall. They'll then go for the South of Ukraine. Unlike the West, Russia doesn't have a deadline to meet. They would gradually take town after town while crippling Western supplies to Ukraine. They already control 20% of Ukraine when they brought the rest of Ukraine to its knees.