uhm I know it's already too late but....is it...Marriage of Convenience?? because a major success in the story occurs when fl uses her knowledge of the future to find a shipwreck containing high-quality vintage wine at the bottom of the sea. She has the crew retrieve it, and it becomes a massive financial success that saves their territory. which is close to what you described... or I'm wrong..,(〜 ̄△ ̄)〜

Hmm i really forgot the tittle but it's about a fl that regressed and instead of marrying someone else she get engaged with some kind pirate ml, he lives on another part of the deathly some kind of sea, which is believed by the ml people whoever go never return but the Fl actually make a good solution and fight mechanism- i think? And i remember bout the last bit that the FL asked the ML crew to find some wine treasure under the sea and sold em or some kind of crystal or whatever is it and it was a huge success and they become a best couple fr matching clothes and stuff