MTFBWY is a phrase used by non-Force users only because the Force can use those people to accomplish things even without their direct attunement to it or realization of what’s actually happening. But saying that to the average person is never gonna result in them shooting lightning out of their fingertips.
Quite frankly, I don’t care if this is one interpretation of how using the Force works coming out of the theater in '77. It’s 2024. We know how the Force works in people according to the prequels, books, and shows we have. And you didn’t really give a good argument to explain it “always being there” in Rey according to TFA and TLJ.
EDIT: Heck, according to your own edit of Starlight what you’re describing is NOT what happens. The dark side awakens in her, the Force never “chooses” her. It’s what retroactively makes the title of that movie kinda badass. It’s never specified which aspect of the Force it is that awakens.
The reason I chose to emphasize Rey’s choosing the Dark Side at the end of the film was to explain why she was able to grow so quickly in power through the film. The Dark Side is the quick, easy, seductive way to power, as opposed to training as a Jedi, which takes years and historically required training from a very young age.
When Rey is first drawn to the Skywalker blade, it could be that she has power similar to Finn’s power in TROS, or Luke’s power when he blows up the Death Star. The difference between Rey and Luke is that Rey quickly and subconsciously turns to the Dark Side to meet the crises she faces in the film, unlike Luke or Finn. This leads to her already having so much power by the time she meets Luke that he is terrified of her, and tells her that she’s gone straight to the Dark. When Rey shoots lightning out of her hands, she’s been on her path of power for over a year, bolstered by the Dark Side and Leia’s training.
So yes, I think it’s perfectly reasonable for the Force to awaken in Rey for the first time in TFA. TLJ even gives an explanation for this power: “Darkness rises…and light to meet it. I warned my young apprentice that as he grew stronger, his equal in the light would rise. Skywalker, I assumed…wrongly.” Snoke basically says that Rey’s power is the result of her opposing Kylo Ren. Granted, Snoke is working under the assumption that Rey is using the light side of the Force, but he also doesn’t know that Kylo is so drawn to the light that he is about to betray Snoke and join with Rey, and that their relationship is much more a ying-yang situation than a binary.