“Most electronics today are extremely susceptible to EMP. I used to doubt this was really a threat so I researched it fairly extensively.”
The truth is, we don’t know for sure, but we do know that just because the energy is there, doesn’t mean it will couple with any particular device. It also depends on orientation, angle of incidence of the energy, and other things.
The biggest issue will be the power grid.
You’re right we don’t know for sure. What we do know is the types of components used in today’s electronics are generally much more sensitive than the electronics used in the 50s when EMP effects were observed from the nuke testing.