I know you’ll disagree but both the concepts of Rey Palpatine and Rey Skywalker serve the theme you’re talking about, that your bloodline doesn’t matter and you choose your own destiny.
But it still means to you have to belong to some great bloodline in order to be strong with the Force. That Rey was actually a random girl meant that it could have been anyone who could rise up to defeat evil and Skywalkers and Palpatines didn’t matter. Anyone could be a hero. That’s broom kid. Now we’re back to, if you’re not one of four families, you can just forget it. Having her be a Palpatine still narrows the story to “will you accept the destiny in your blood or reject it” which is Kylo’s and Luke’s journey again as opposed to an open ended question of “who and what will you choose to be when that question is truly yours to answer?” I found that much more interesting than Rey Palpatine.
I originally felt the same way because Finn and Rey were sharing equal time and both were ordinary people scraping by and trying out lightsabers and Jedi stuff and getting lucky. But then Finn was kind of sidelined in TLJ, and Rey didn’t actually get any training from Luke. I was never one of those people that said Rey was a Mary Sue, but I do think that her level of power and importance should be explained somehow.