But then again, she's made herself pretty clear that she'll leave once Kaido's overthrown.
Not a conflicting statement at all, nor indicating any intentions to stay and usurp Momo and The Scabbards role in the post Kaido Wano-era.
She definitely did say that. That's nothing I argue. However what I see to be able to at least create a moment of inner conflict are very recent new developments. It's just within the past three chapters, that Momonosuke has not once but twice shown that he's still got a long way to go and definitely needs all the support he can get (which is natural considering that he's still a little boy). He openly declared in front of Yamato, that he doesn't want to open Wano's borders and Yamato looked surprised to hear that. And now he even said that he wanted to surrender until Yamato had to snap him out of it.
I'm not saying that this is clear proof that she will stay behind. Far from it. However these are new developments which shine things in a new light to her. And if she's anything written like a believable character, then the idea of helping Momonosuke on his way should at least cross her mind now. It doesn't have to replace her desire to leave, but it should be a natural thought to have. Yes, the Scabbards are still there. But that doesn't mean that she cannot have the feeling that she needs to help Momo herself. Especially since these recent developments directly connect to Oden's desires she that are so precious to her.