After reading chapter 18 and 19, I must change my first theory about the FL and original story FL souls being mixed up when reincarnating, and instead speculate that after the original FL funded up in her first story run through (or after story) the powers that be reset the timeline and since they couldn't really remove someone they already reincarnated they brought in another more befitting sole and placed it somewhere where there was a chance to meet the ML, hence our FL being reincarnated into a body that will be threatened if she herself doesn't change the story.
After reading chapter 18 and 19, I must change my first theory about the FL and original story FL souls being mixed up when reincarnating, and instead speculate that after the original FL funded up in her first story run through (or after story) the powers that be reset the timeline and since they couldn't really remove someone they already reincarnated they brought in another more befitting sole and placed it somewhere where there was a chance to meet the ML, hence our FL being reincarnated into a body that will be threatened if she herself doesn't change the story.