Assuming the Russia speculation is correct, what is their motivation? General chaos in Europe? It seems pretty reckless knowing this would be ascribed to them, and I don't see how they benefit here.
Retaliation for Ukrainian attacks on Yandex datacenters most likely - it communicates to EU states that Russia has capabilities to physically impact their infrastructure via cyberattack, which should act as a deterrent for sending aid or admitting Ukraine into the EU.
I don't have any insight into this situation, but I feel like the incentives to blame Russia for any problem must be tremendous.
It's a perfect 'get out of jail free' card for any sufficiently complicated screw up.
As long as they can avoid loss of life (or significant loss of life) and direct attribution, but the rumors are still that it's Russia, this is a way to reduce popular support for Ukraine. The attacks aren't severe enough to make people want to support Ukraine to spite Russia, and it makes it apparent that there is a cost for the current support.
How does firebombing the British PMs home benefit Russia? How does flying explosive laden drones into European airports benefit them? How does bombing Kiev benefit them? Russia still does it
Part of the goal is to be a nuisance so Europeans pay a price for supporting Ukraine, in the hopes that we decide it's not worth the heat. Russia is banking on the west's refusal to face a conflict and the sacrifices it causes, kinda like a game of chicken.
We're about to hit a series of important elections as well (Spain, France, I think Germany soon as well?), hybrid warfare is supposed to influence in favor of extreme parties.
It's a major issue. On paper NATO can mop the floor with Russia even without the US backing, but nobody in a first world country wants to die in a ditch, and the endgame there is also unclear because Russia can play the nuke card if they're too threatened.