> The EU is clearly otherwise willing to watch Ukraine fall.

All the money, humanitarian aid, weapons, intelligence, training and geopolitical backing beg to differ.

Did Russia say they did it? No.

So you can weaken your opponent without getting the backlash.

I'm not saying Russia did it, just that they could be the cause of this. Weakening Europe is in their interest, and they already have blatantly done smaller scale sabotage. It wouldn't weaken their position, as you said, Europe is not really interested in taking Russia seriously atm. Sabotages, killings, politician corruption and public disinformation have been common tactics for them for a decade now. Now that Russia's #1 enemy is under their control, I'm not sure they are afraid to take on Europe more directly.