Old whitebeard (Strongest PIRATE in the world)
Old Roger ~ Old Newgate
Seems as if Rayleigh and Gaban the wings are also on that footing.
Old Roger ~ Old Newgate (canonically) > All Yonkos
With Rayleigh and Gaban being on similar levels , be it weaker or stronger decisively they’re all on the same ballpark at the very least.
Old Roger/Newgate >~ Old Ray/Gaban
Kizaru > Old Ray, left him puffing quite quickly if the battle had dragged out Zaru would’ve pinned him still with energy left to spare
(Kizaru wasn’t even caring about Rayleigh even when he got interrupted in executing zoro, only cared when Ray had stood as an obstacle when Zaru was going after the strawhats)
Old Roger / Old (healthy) whitebeard THE STRONGEST PIRATE <~ Kizaru and other admirals
Therefore on average , an admiral is stronger than a Yonko , Admirals > Yonko.