I haven’t had the chance to watch the video yet, but as an electronics engineer as training, if you want to blow your birdy brains try understanding the propagation of RF along a coax cable…then try how an aerial works…and for Einstein level,
try RF down a waveguide as used on most radars. Nearly forty years on I’m still struggling with the concept that energy would rather travel down the air in the middle of a bit of waveguide than the solid bit of conductor that surrounds it!