Somebody is refusing to pay protection money and is forming a “neighbourhood watch”. We need to make example of them.
The actual Russian perspective is "Let's quickly grab Ukraine before they completely turn towards Europe, otherwise Russia cannot be an empire again."
It may be strange to modern western minds but Russians still consider their imperial project as wholesome, good and nearly sacred. To get into the correct mindstate, you can read for example how Churchill venerated the British empire. The Russians hold this same veneration to their imperial project today. They also know western audience probably would not appreciate this reasoning so they need to invent laughable excuses like ”we were afraid of NATO expansion” that clueless western commentators happily repeat as the foundational reason.