By the time you move that pen light to an equivalent distance to the sun
your pen light would be so diffused you would be in near darkness.
It doesn’t have to be an equivalent distance. Just far enough away to hit 50% of the globe.
And you can also use it parallel to the surface to disprove prove every dumb ass thing you’ve said about horizon lines.
Really $15 and 1 hour will show you that all flat earthers are wrong.