Using the Toyota Prius as a backup generator is a modern day version of running equipment from the power take-off on a truck. I had insulation blown into the walls of a house I used to own. The truck engine ran all day powering the blower for the insulation. We had our carpets cleaned and the engine on the van ran the vacuum to suck up the cleaning fluid from the carpets. Fire engines run the pump from the power take-off on the engine. I can see where it may be feasible to use the Toyota Prius as a generator.
Absolutely!
yet Google did not show any "ready to go’ solutions to tap into the high-voltage lines of Prius, which is the most appropriate place to tap into
tapping into 12V connection makes for this simple math: for every kilowatt of power you want to draw, you need 1000/12 = 83 Ampers of current, this is taking no spare capacity needed to compensate for inefficiencies, so this idea is dead in the water for anything of appreciable power draw
want to tap into all tens of kilowatts of power Prius has to offer?
high-voltage lines are your only choice
I’d never go with one of the 12V solutions. To many ways to mess up a $25,000 car.