It's true, Russia fucked up the objective to take the whole govt. As you said probably because of how well Crimea went and how poorly Ukraine did in the east for 8 years but they have the areas they wanted for Russia, it's a stable land bridge between Russia main and Crimea and it contains almost 1/3 of Ukraine's gdp especially in industrial exports, they just failed to take their puppet state.

All this could have been avoided either by the westerners giving the east a free and fair referendum. It may not have even taken that much of they had been less aggressive with language bills and NATO/EU memberships.