If electrical grid is up, internet is up.

If electrical grid is down, we're looking at a truly apocalyptic scenario, and everything you said is moot. If that happens, no one will be concerned whatsoever with money of any sort. They will be concerned with survival - specifically water & food, heat & shelter, medicine (especially antibiotics), and guns & bullets - in that order.

Bitcoin will not matter one iota in that scenario, and neither will any fiat, any precious metal, or any other resource that cannot be consumed or used to kill or heal. Lead (bullets) will be the only "precious metal" left, and a pound of it will be valued lower than a glass of fresh water.