Russia's biggest asset is general apathy in the rich West. People with names written in funny script that sound like Bond characters shooting at each other a thousand kilometers away is hard to get Peter and Paddy and Pierre and Pontus and Pablo living comfortable lives with comfortable jobs to give a shit about. There's a reason Western governments make sure the media prints stories about intercepting Russian jets.

Bringing the war to them and getting the public to want their government to commit blood and treasure to doing something about it is a ferociously poor strategic decision from the Kremlin. "That Putin killed a 17 year old French girl on her way to school on the train" is unlikely to cause the public in the West to back down.