We use our Kranzle PW for engine bay cleaning on all of our used car reconditioning and for detail clients. Never had an issue come of it. PW caps out at 1400 PSI, we only use the 40-degree nozzle and we still keep the gun a few feet away from the engine.
Just check the engine over before cranking for signs of water pooling, like the early 2000s Ford Zetec engines where the ignition coils sat in a U-shaped trench in the valve cover with no way to drain. Wet vac out any standing water, then crank.
Fuse blocks, alternators and underhood electrics in general have come a long way in the last 30 years, as you will notice most modern vehicles barely have an air deflector, let alone a splash guard to seal from water coming from underneath anymore, unless it's a performance car or vehicle with off-road intentions.