I'd tell you to go back and re-read Wano, but I'm not wishing that one anyone right now. Yamato did get better, her Oden moments are more jokes, rather than her actually introducing herself as a dead man.
You have to realize that the Straw Hats and Samurai are the first friends Yamato has ever really chosen on her own.
"I'm Yamato's Kaido's son!" Ignoring the gender stuff, Yamato is comfortable introducing Yamato as Yamato. That's progress.