This chapter also pretty much confirms that Yamato wants to sail out to sea most likely because of the stories she heard in Oden's journal, it isn't just because she's trying to be Oden, she's doing it for herself too. She's also not stupid like people assume her to be, she calls herself Oden because she idolizes him, that doesn't mean she believes she is Oden all along or the fact that the real Oden never existed. She called herself Oden at a young age and for a long time so she probably got used to it and just stuck with it, no wonder Kaido is pissed off to no end and is suicidal lol.
In a way, Yamato is like Luffy, who wanted to be the Pirate King like Roger after hearing the tales and stories from Shanks. She is also ambitious as she said that she wants to get stronger even if she does manage to leave Wano and escape from his father's captivity.