Wano and 4 Emperors Saga has been all about who characters really are.
Sanji and Germa. Kaido and Fake Joyboy. Luffy and Nika. Yamato and Oden. Momo and becoming a true Shogun.
Nami's whole arc in Wano and 4 Emperors Saga has been about Motherhood and her devotion to Luffy.