The author explicitly hyped it as magnitudes inferior by virtue of not making them skysplit.
Kaido and Luffy's clash reached dozens of kilometers into the sky, split the sky dozens of kilometers wide and changed the weather, but sure, sending some fodder flying is superior.
Larger lightning = stronger has never been a thing, you've literally just made it up.
Xebec was also conflicted, they were both holding back so it is impossible to scale from that fight.
Harald is not stronger than prime Whitebeard.