If it's "he who shall not be named", gotta admit, that's a clever strategy: ramp up sabotage and see how NATO/EU will feel about their "red lines", and how well does that article 5 really work in practice. Is it worth more than the paper it's printed on? Let's find out!
People have been laughing at the West crossing multiple Russian "red lines" and the Russians not doing anything. So the Russians can follow a similar route: a cable torn here, a warehouse blows up there, maybe a bank website is hacked, water supply or power station company blows up "randomly". Is anyone going to launch nuclear bombs because of that? That's absurd, of course not, yet NATO/EU just looks weak and pathetic in the process.
Ideally, these countries should ramp up similar acts of sabotage on the Russian territory if they confirmed that's exactly who it is. A dam fails in Siberia, maybe the payment system goes down for a week, a submarine catches on fire while in port for repairs. Honestly I don't think they have the guts to do that.
Some regimes only speak the language of power. They have to be believably threatened; calling them on phone to chat and beg for them to behave, is just showing more weakness. Scholz just called Putin. Anyone remember Macron talking with Putin for tens of hours at the start of the war? A lot of good that did. When they see a credible fist in front of their nose, that's the only way they'll stop.