myfirst..yes the speed of light from anything that cannot reach it
target is 0.

No, the speed of light is nonzero. If there aren't any photons available to
reach a target, then by definition it's not light so it can't have speed.

same with sound.

The amplitude of sound decays to the point at which there is no sound (eg.
no one will hear your voice 100 miles away because the sound has died out -
not because it's slowed to zero; although, I imagine the hot air coming out
of your mouth is so significant that it causes local atmospheric changes
that may encompass a radius that large).

power does effect speed over distance.

That's not what you said earlier. Changed your mind?