I hope somebody building and selling microgrids and energy storage systems is ready to take advantage of this situation. Mass deployment of batteries at the grid edge is a great idea for a lot of reasons, but none more immediately compelling than "the power won't go out if the grid goes down."
It should be mandatory for critical infrastructure like ATMs to have 24hr batteries installed. And some sort of power backup to maintain internet access as well - even if it's just a matter of everyone being allocated a small amount of starlink data or public wifi. These things have relatively small costs, but make the system much more resilient.
You should probably just keep some cash on hand. And keep an FM radio and a few batteries on hand.