I saw somebody shipping Dadan and Whitebeard (I think they called it Dadshipping but I Cannot find the post rn forgive me) and like obviously it's a crackship but I am. Compelled listen hear me out
The real lynchpin in all of it is Ace, and Dadan and Whitebeard's wildly different experiences with/approaches to parenthood.
Whitebeard obviously intended to build a family for himself right from the start, he was willing to adopt the kids who needed him and thus he did exactly that. He has found purpose and joy in fatherhood.
Dadan very much did not intend to become a mother, least of all to fucking Gold Roger's son. She struggled to take care of Ace in the beginning, and by the time she might have started to hit her stride Ace had closed off, and neither of them were able to connect with the other in any real way until the fire. But Dadan loves the shit out of Ace and his brothers.
I think there's a lot of really interesting avenues to explore there regarding Dadan's experience in raising Ace, particularly through the lens of the trauma of motherhood, and I think Whitebeard could be a really big influence in the two of them finally working through the lingering issues they have and admitting that they do see each other as mother and son. I also think that Whitebeard would respect a woman who ran into a fire and swung an axe at a pirate to protect her boys, even though Dadan is very not cut out for the kind of battles the Whitebeards regularly get into. That's fine. Dadan doesn't want to be that kind of crazy fighter, and she doesn't pretend to be.
I can picture Dadan resolutely refusing to admit she finds Whitebeard funny and charming and Whitebeard absolutely taking it as a challenge. He makes a joke and she cracks a tiny little "Pfft--" and he fucking WHIPS his head around to stare at her but she's white-knuckling her own knees to keep her poker face in place she absolutely will not give him the satisfaction of seeing her laugh.
Also I think it would be hilarious if Shanks is dating Makino and Whitebeard is dating Dadan and Shanks is leaving Dawn while Whitebeard is arriving and they look at each other like that scene from The Umbrella Academy.
Also also all the Whitebeard Pirates react to Whitebeard putting the moves on Dadan like hey good for you pops you still got it but Ace sees this happen and scREECHES