here is the problem with this
You could say that what Roger and Whitebeard did in that chapter was a Conqueror’s Haki clash cuz both are confirmed coc user
But what Garp and Kuzan did wasn’t necessarily a Conqueror’s clash, since Kuzan has never been confirmed to have Conqueror’s Haki. Some might argue, “Oda will reveal it later,” but if Oda and his staffs didn’t reveal it during Egghead, what makes you think they will in the future? The fact that they confirmed Garp as a Conqueror’s Haki user but not Kuzan should be enough to tell you he likely doesn’t have it.
The same logic applies to Kizaru Oda fully showcased his abilities during Egghead, and we can safely assume he isn’t a Conqueror’s Haki user either.
Another example of a massive black lightning clash that isn’t a Conqueror’s clash is this:
Yeah, I don’t think what Nusjuro and Zoro did was actually a Conqueror’s Haki clash
