The portrayal that the likes of Whitebeard (WSM), Big Mom (could've been Fleet Admiral) and Kaido (WSC, Gorosei afraid of him) are all greater than what the Admirals have had. There's also the fact that all of the Yonko except BB and Buggy have CoC, whereas only Sengoku on the marine side is confirmed to have it.
Yonko and Admirals are all top-tiers yes, but it's been shown pretty clearly that the Yonko are still ahead overall strength-wise, even if the gap isn't that big.
NO its not how portrayal work .
1 every single admiral can be fleet when we calling power . BM was hyed to be abel to reach the top of the navy jsut like she reached the top of the pirates.
The titles for what we seen are only gift to pirates and there must be a reason for that for exemple it cna be simply beating the previous owner in 1v1 tought I doubt it it seem some time that the title was gift for the character.
GOrosei being scared of kaido is nothing there is not an admiral actively facing them the same way if Akainu would ahve wanted smoke when he was in front of them you can trust me there would have been some sweat drops .
Sengoku was also said by roger to be someone that have a chance to capture him or to make a fun fight we know that for having a fun fight roger need ahrd diff at the miminun wich mean sengoku is at worst a hifhgt dif for roger Fleet admiral have a great portrayal especially comapred to yonko .
Let'S not forget jinbei call the yonklo a mere yonko . When it is an admiral in front tought he talk about how he is ok with dying .
IM not saying that admirals are stronger but nothing make a yonko stronger.
GArp was just as strong as roger until prove otehr wise they were relative in strenght .
SO the strongest Navy have to be as strong as the strongest pirates it always was the case and I don't see it changing.
The strongest yonko should be the match for the fleet admiral or the pirate king should be his match .
When the other admirals match the other yonko (Except buggy)
Because Oda clearly stated by this statement that not a single group is better then the other one.
SO if you think the yonko are stronger then the admirals in average the fleet will be massively stronger then the yonko for equilibrate it and the fleet will be the reason you need to beat the admirals and not just the yonko.