Bruh....
Bigmom, a yonko, was disrespected by oda. But all of the warlords were respected. THAT IS THE POINT. Even a yonko is expendable to oda while warlords aren't. They are the whole reason the story is as long as it is.
Hancock was NEVER paired with coby. He was begging her to surrender cause they couldn't do shit to her. In fact, they were having trouble with the Amazon lily fodder lol. Coby was clearly bleeding even before Boa got in the fight. She used slave arrows. That means coby just dodged or even hid behind someone. BB came for Boa. And when he didn't get what he came for, he settled for coby lol. "Just as important"