Tbh, I can see a woman lead Wano, either it's Hiyori or someone stronger. Kaido's plan to make Yamato as a shogun is confirmed my headcanon.
History has outlined, women should not be emperors of Japan. Looks like Oda will take that constitution to make his own Japanese dream land. Making a woman as a shogun. Looks like Hiyori will become the Shogun instead of Momo until Yamato is introduced to us and she's big fan of Oden. Coincidence? I don't think so. We don't know her mother yet. If her mother is Wano's citizen that will confirm 50% of my headcanon.
And if Yamato really wants to become Oden, joining SH is not the way. She will remain in Wano and become shogun under Luffy's protection. In addition all of candidate of a woman country leader has nami's template.
If her dream changed in the end of arc I can see her joining the SH. Or at least Oda can give her another power that not based on thunder/electric thing like thunder bagua, we already have Nami and Carrot to perform such a thing. Or maybe ancient/mythical zoan df.