if Ryokugyu was not serious, Yamato didn't even use her DF, but I would expect no less from someone comparing King who got humiliated by Zoro & Ryokugyu to someone fought Kaido 1 vs 1 for a long time & hurt Ryokugyu with her first attack.
the fact that Yamato never got humiliated, even though she fought Kaido & Ryokugyu, makes her automatically above the likes of King