A coup and a seizure of power took place in Ukraine, and only after that, and from that moment onwards, Russian views and methods became completely contradictory to the Ukrainian leadership .
After that, Crimea returned to Russia, not the other way around. Therefore, the deterioration of Russian relations with Ukraine has nothing to do with Crimea.
There was no coup d’état in Kyiv in 2014; this is a longstanding pro-Kremlin disinformation narrative about Ukraine's Euromaidan protests.
The spontaneous onset of the Euromaidan protests was a reaction from several segments of the Ukrainian population to former President Yanukovych’s sudden departure from the promised Association Agreement with the European Union in November 2013, as a result of pressure from Russia.