Gorosei being scared of Kaido is such a nonsensical argument considering Saturn had no fear at all and went to God Valley where the Rocks pirates had an entire war with the navy and Roger pirates. There were at the very least 4 characters stronger than current Kaido (Primebeard, Xebec, Roger and Garp).
All of the Gorosei are, unlike Kaido, awakened, have ACoC. They also have mythical zoan and immortality.
Nasujuro even has a special graded blade, only 12 exists in the OP world and guess what, so far we've only seen Roger, Mihawk and Primebeard using these.
Now all these 5 top tiers bow their head to Imu. If this isn't a statement of pure power, nothing will make y'all understand it but keep waiting +500 chapters to see if Imu jobs or not.