I haven't read Dragonball but narusaku never made sense. One Piece is still going on. Why do you keep comparing it to long ended manga? In today's shows, the male lead and female lead often become a couple, or show romantic interest (MHA,Black Clover, Attack on Titan). Even D. Grayman. By the way, erehisu fans in Attack on Titan were guided by a similar logic and lost.
Dragonball Leads:
Goku and Bulma
Goku marries Chichi (girl obsessed with MC)
Naruto Leads:
Naruto and Sakura
Naruto marries Hinata (girl obsessed with MC)
Bleach Leads:
Ichigo and Rukia
Ichigo marries Orihime (girl obsessed with MC)
In One piece, who’s the girl obsessed with Luffy?