I don’t know what an EMP burst would do to the electrical grid. All I know is that if city folk are without electricity for even a short period of time, things get nasty in a hurry! Rural folks with their own well and septic and generator will do fine for much longer. For city folks, especially large city folks, the loss of electricity would lead to loss of sewage treatment/removal, loss of drinking water, and loss of refrigeration.
Our society, especially the generations of the last 60 years or so, have grown up with the ability to get their food or water on a moments notice without having to plan ahead. An interuption of that immediate source of food and water and sanitation would make big cities a mess with the power going to those groups organized with guns and the desire to use them at will (gangs).
I would not live in a big city in these sketchy times. You may be a great shot, but without numbers, you’ll be over-run. If you have a family, the amount of stuff you’d have to have ready to bug-out, is a lot, and there is no guarentee that roads will be useable (probably clogged or patrolled by gangs/groups).
Regardless of where you live, rural or urban, become part of some kind of group with like mindedness on survival. United you can stand, divided or individually, you will fall.
Read the EPRI paper above ... Geesh. Quit guessing.