@Fujishiro Kuzan or Kizaru being as strong as Kaido wouldn’t make much sense.
In One Piece, there are 3 primary factors in determining your power level:
1. Your base physical stats, obviously
2. DF
3. Haki
Kaido’s base stats are obviously better than the Admirals’
Kaido’s DF is also better or at worst equal to theirs. Ginny said Mythical Zoans are the best type of DF, and this is supported by the narrative (the MC and final villains all having Mythical Zoans). Even if you go by the other translation which only said Kaido’s DF is one of the strongest in existence, that still means Kuzan’s and Kizaru’s DFs are only at best on the same tier as Kaido’s in Oda’s mind. And like Kaido, they don’t seem to be Awakened either.
Kaido also has objectively better Haki. He has all 3 Adv forms, while the Admirals are only confirmed to have Ryuo, and both of them (especially Kizaru) are very unlikely to secretly have ACoC.
So if Kaido has them beat in physical stats and Haki (the most important of the 3 factors), and they’re only at best equal to him in DFs, how can they be on his level?