Whether or not you are right about the Maidan uprising, it was known from the time it was announced that Ukraine and Georgia would be invited to join NATO, that Russia would not allow it, and Yanukovich shelved plans for membership.
It's not Russia's choice. Sure, they get to make a pitch, but rather than send messages to the Ukrainian people they sent Rubles to the Ukrainian president.
This would be why Russia suported him.
The word you're looking for isn't 'supported' it's 'bribed'.
All Ukraine had to do to get Russia out of Ukraine was maintain neutrality.
Russia weren't in Ukraine at the time. They decided the best way to keep Russia out of Ukraine was to have the support of NATO; turns out they were wrong, but neither option would justify Russia's invasion of a foreign country - you don't get to invade because you don't like someone else's decisions.
Now they have lost 5 regions, and the weapons sent by the West aren't pushing them back but making Ukraine weaker.
They're not pushing Russia back at the moment - they have been, and they might again. Equally, Russia might run out of money, men and resources, it depends on which way Donald Trump's coin-flip lands at the moment. It's going to be a long three-year wait for Ukraine to get the backing of a US president with a spine.
Not to mention that Russia is now closer to China, an unwelcome alliance from NATO's point of view.
NATO, currently, doesn't give a toss about Russia's lack of military capabilities, if China wants that liability it can have it.
O.