I need spoilers.
Based from my understanding FL is someone sent by the gods to stop the catastrophe.
ML has been reincarnated multiple times and in those times FL doesn't really get the happy ending route no matter how much ML tries to help FL so in the last time line I think ML tried to make FL stronger to overcome the catastrophe resulting in FL to lose everything despite winning the war. That's why FL was cursing ML that she despises ML going back to the current timeline I think the reason why ML married FL is to stop her from fulfilling her duties.
I think uwu
I am giving this a chance since 9 chapters won't actually tell everything. I love that there are a lot of things that still hidden like the fact how the FL saved the ML. There is also the background of the ML on how he became a "monster" and how did the FL was isekai-ed in the novel.
Since there are so many tropes where the FL was actually the real owner's body being transported to the real world then going back to the novel, or the normal real world isekai-ed thingy.
There are a lot of things to be unearthed and nine chapters are too little to give it all.