By the time the Russians decided to send actual forces instead of just undercover puppets, there was nothing you could even remotely call "banderite" in power in Kyiv. Because as flawed as the Ukrainian democracy might be, there were actual elections and those right-wing parties that briefly took power after 2014 had long lost it by then.
Those self proclaimed republics also didn't have real democratic legitimisation nor was there broad support in these regions for asking the Russians to intervene.
The rest of your argument is more circular logic, and nostalgia for regimes propped up by petro-dollars in it's later years is neither uncommon, nor does it reflect in actual voting behaviour of these very same people today (if they are allowed to vote in free and fair elections).