> Personally, with a high-wing aircraft, I’d like to
see a purely mechanical fuel injection system fed with gravity fuel > flow – do away with the redundant (electric) fuel pumps, 4 (electric) injectors.
Then plumb a line down to your throttle body with an accessible manually controlled needle valve. You'd probably never be able to start the engine on that, but if the electrical system goes south, it would keep fuel flowing and let the battery run longer.
BTW, except for the few diesels flying, all airplane engines are electrical dependent. Magnetos just happen to have their own generator buried inside.