the creator of that movie made a sequel to it where he acknowledges that it is unusual and explains it by tying her by blood to the most powerful Force user in the galaxy.
I really don’t think they thought that hard about it. I think they just kind of thought “Fuck it, bring Palpatine back” in the eleventh hour and then thought “Fuck it, make Rey a Palpatine, it’ll be a mind = blown moment or something.” I never took it to have any meta meaning like that, nor did I ever take it to be any sort of explanation of Rey being powerful. I didn’t realize anyone took it that way until hopping onto the cybertubes.
I mean, Kylo does say “You have his power”, but I always took it to be just your average sub-par Star Wars line.
But lightsabers have never been described or depicted as light.
/s