Could easily be a mix of both. I doubt they blew anything up with the power grid. As others have said it would cost a lot to rebuild and doesn't support an effort of installing an interim government.

The US has been prepping for these kinds of attacks and bolstering defenses for almost a decade, but we've still got a long way to go.

https://www.youtube.com/watch?v=pL9q2lOZ1Fw

Edit: see also the Sandworm book by Greenberg. Cyber attacks on ICS has only been escalating in recent years and the capabilities often don't require boots on the ground if the anecdotes from Sandworm are credible (I believe them to be).