Before realizing that Roundhead Rian wanted to destroy star wars, as I was watching TLJ, I always thought that big reveal was going to be that Luke abandoned Rey on Jakku, to hide/protect her. She was a padwan in his school so didn’t remember her parents (setup in TFA), Kylo was older than her, so he would remember her joining the school. When Kylo and Knights of Ren attacked the school to kill the padwans, Luke was able to gather a few children and escape, one being Rey. So when Rey was looking at the ship, she was sad that Luke left, who was basically her father (…or may her actual father…sounds like JJ Abrams hadn’t decided). But at that point, she could’ve been related to Luke, Obi-Wan, or even Leia still (since all she remembers was Luke at the school, having been adopted by the school very young). Of course, Roundhead Rian destroyed all that.
These movies were popcorn movies; nothing complicated about them. JJ Abrams had it setup to explain why Rey could use the force…
Abrams deliberately had it set up so that any twist could theoretically work. Not matching your headcanon doesn’t make something bad.