Someone thinking something doesn't = Is capable of doing it
Just like Luffy thought he cant lose then lost right away.
Doffy is deluded enough to think he can jump and admiral, although it would be difficult. Him trying to jump Aokiji for example would end in a disaster.
All you're showing is Doffy severely underestimates the power of Admirals, because they are government lapdogs, but doesn't underestimate Kaido's strength, because Kaido is a stronger tyrant than he is.
Again, doffy was deluded enough to think he could kill smoker from range 0 before kuzan could stop him, and he failed even that. Then when Aokiji let him break out the ice, doffy starts internally crying and asking questions like;
"Waaaah why are you here? what do you want kuzan? what are your motives waaaah" then he silently backs down once he realises he's not gonna get his way.
Anyway using admirals for kaido's portrayal is one thing
, but if you compare yonko to yonko the point remains:
The only reason Doffy could act nonchalant and laugh when witnessing Old washed WB's power is because he wasn't directly involved with WB, and had no intention of it:
Again, hence why he asks Mihawk if he is seriously going to fight because in his mind "why would anyone ever want to purposely try to get involved with a yonko?":
"Heh heh.. what are you doing? are you
really going to fight?" = What the fuck are you doing? are you really going to battle against a Yonko and his crew? something I would never purposely do?
Both these panels are in the literal same chapter btw, Doffy reacting to WB's power, and being surprised of Mihawk wanting to get involved. Mihawk and doffy witnessing WB's power and having opposite behaviours shows you the kind of men doffy and Mihawk are.
If WB was breathing down Doffy's neck, expecting results, he would be shitting his pants the exact same way he was for Kaido, that is the fact of the matter. Because of WB's portrayal in the world.
But as a matter of fact it would be the exact same for Shanks and BM too. So this whole propaganda post to elevate Kaido using doffy's reaction doesn't work.