I just want to share with you, an isekai reader with platonic yandere Shanks made with some random women he have a one night stand with at some bar. Which conceived reader, reader mother's passed away in labor
Shanks knowing that feel very guilty and take care of readers the best of his abilities, carrying her, feeding her etc.
While reincarnated as a Shanks daughter, darling doesn't have Shanks physical and strong haki power. Instead she was born weak and frail, getting easily sick making Shanks give her a staff made of Adam Woods that can be used as a secret inventory keeping something inside of it
Even though darling have a frail and weak body conditions, for some reasons because of her status as a reincarnated person, haki user can't sense or see her future adding to that she have a very strong potent blood and healing power that can heal curse, wound and dying ailments. Along with a strong shield that cantbe pierced, and a power to teleport to any place she want but with a catch. She need to imagines the place first then she can teleport
Darling having enough with the pirates life with Shanks, decided to escape from the red force in the middle of the night by stealing billions of berries and putting it inside her staff, she used the memories of traveling with her father to imagines an island to teleport to.
And so begin a chase of father searching for his daughter, and darling trying to live her life as a tourist.
But since she can't travel to a new island without seeing the place first, she hitch a ride with pirates she meet along the way. Because she think it's safer with them than travel alone, in case Marines searching for her.
Along the way darling kind of unintentionally make most of the pirates fall in love with her, but before anything can happen darling just run away after they arrived on an islands.
While darling running around island to island, Shanks got info from his connection of the sighting from his daughter running around being pretty and oblivious to her charm as she take an interest of so many pirates making Shanks have so Many heart attacks from it.
The thing about the One Piecw worlds is that I like to imagine once one pirate (or more in case of a polyamorous route) get(s) involved, the rest of the cre basically becomes a platonic Yandere for them. Being Shank's daughter and being raised by him and his crew basically means everyone on that ship is reader's uncle figure - even Yasopp who spends more quality time with you than he has ever with his own son. Even Mihawk has a soft spot and the only reason he bothers to come around at all is to check up on reader, probably trying to convince her that under his mentor ship she would learn far more than under her perpetually drunk father's guidance.
Being the daughter of such a feared Emperor also means that reader has a hefty bounty put on her head simply for sharing his bloodline and explains why the entire Red Hair crew is so protective of her. Despite best attempts to conceal the fact that his daughter at one point escapes, word eventually gets out and then chaos follows as everyone is secretly after reader who is constantly being underestimated which she uses frequently to her advantage.
I'd like to think that reader has not only plenty of romantic Yandere but also platonic Yanderes after her the more time she spends outside. Other Emperors like Bog Mom for example who wouldn't mind another daughter in law and is busily offering her own sons and daughters as potential spouses to convince her to join them as her powers would also greatly strengthen her powers.
The Cross Guilt is probably also after her though only because Mihawk is basically the enraged and worried uncle who cannot believe that Shanks has actually lost his daughter because despite his constant passive-aggressive comments, he still expected Shanks to do better.
The Whitebeard Pirates would be an obvious choice too. Maybe reader met Ace on his solo travels and he offered that she could travel with his crew for the time being which ends with him getting romantically attached and Whitebeard adopting her within his mind as his new daughter-in-law.
Eventually she is going to end up with the Straw Hat Pirates where Luffy quickly takes her in as she is the daughter of Shanks whilst he together with people like Zoro, Nami and Sanji and maybe also Robin if the age difference allows it could get romantically attached if we assume she is in her early twenties.
Meanwhile Shanks is getting a heart attack because he is constantly subjected to the rumors of Big Mom having tried to set his daughter up with one of her own or he may even receive a hopeful letter from Ace where he declares that he is intending to woe his daughter and marry her before he finally receives the news that she is travelling for now with Luffy which may be the best option he has gotten so far.