The leaks came out 3 months before the release, just after the reshoots
https://www.reddit.com/r/StarWarsLeaks/comments/d5i0ye/the_basic_plot_of_the_rise_of_skywalker_updated/
That’s when that version of the leaks came out. A good chunk of the information in it was leaked long, long before then. As somebody who obsessively checked leaks on the movie, ‘Rey Palpatine’ came out in what later turned out to be credible leaks LONG before the JediPaxis leaks.