How can you debate this? Do you refuse to know what the hell is a WSC?
And Oda used the word 'Saikyō Seibutsu (最強 生物): which translated as The Strongest Biological Being / The Strongest Creature Among All Beings. Seibutsu includes all living things in the world, including humans. The reason why free manga sites misspell Kaido's title is because the English word "Creature" has plural meanings, but in the original scan there is no ambiguity because the word 'Seibutsu' is the one being used, which is why Kaido was not given the title "Strongest Man" or anything like that, because he is simply not human.
Kaido's title isn't ambiguous at all in the japanese version, his title 100% include humans.
You can do a quick research on what Seibutsu mean:
https://en.wiktionary.org/wiki/せいぶつ#Japanese
living thing, life, organism, creature .
https://www.kanjijapanese.com/en/dictionary-japanese-english/seibutsu
seibutsu creature 2. seibutsu living things.
The ambiguity only come from people reading the English chapter and assuming the word "creature" is to be understood in the animal sense.
In japanese it clearly mean Kaido is the strongest living organism/thing and quite obviously humans are living things.
Kaido's title 100% put him above any human alive in the series, the only way Kaido isn't the strongest character is if his title is fake in the first place or if someone surpass him in the future.