Never forget guys. If freedom is indeed Yamato's dream. It's doesn't mean it must be achieved on the sea necessarily. The sea was Yamato's goal because of the model of Oden and constructed in contradiction to Kaido's goal to make them the Shogun.
But Yamato still has room to really apply freedom with a big F. By choosing to stay, on their term to protect Momo but also Wano, Yamato would achieve REAL freedom.
After all, their is no bigger freedom than to be able to choose your own path with your own rules.