Commodity hybrid PV inverters are now very capable of offgrid/island mode - I have one. If the grid goes down (which it does - I live rurally) I can flip a changeover switch and power my whole house from PV or battery up to a limit of 5kW, which is plenty to keep everything necessary running.

It’s not a mainstream feature and there’s a high setup cost but the tech is readily available and the price/kWh of home batteries is going down steadily.