On an exact level, yes King is stronger than Queen. On a vague level, relative to high-tiers like Kaido and Admirals, they are equal.
Also, Kaido could not have taken both King AND Queen because then Wano would be too defenseless.
Because Kaido took King and left Queen behind, this means that Kaido likely entrusted Queen to guard Wano from outside threats sort of the way Big Mom left Katakuri at Totland when she went to Wano.
Okay, let's use Bounty argument.
Kaido's bounty - 4.6 million
King's bounty - 1.39 million
Queen's bounty - 1.32 million
Relative to Kaido, King & Queen's bounty is roughly equal.
Also, Kaido could not have taken both King AND Queen because then Wano would be too defenseless.
Because Kaido took King and left Queen behind, this means that Kaido likely entrusted Queen to guard Wano from outside threats sort of the way Big Mom left Katakuri at Totland when she went to Wano.
Okay, let's use Bounty argument.
Kaido's bounty - 4.6 million
King's bounty - 1.39 million
Queen's bounty - 1.32 million
Relative to Kaido, King & Queen's bounty is roughly equal.
Crydo rely om the waterful, Yamato and fooders to defend Wano