KKG with mediocre hardening broke through God Thread + spiderweb and hit Doflamingo so hard, that he flew into the city with such impact that it bisected a part of the city and flipped it over.
And did Doffy get his head cracked or something like that ? Also Doffy's attack didn't halt KKG which would mean there is a waste of energy it got overpowered instantly and hit Doffy in his face who appeared to be ok afterawards .
Now imagine KKG with advanced barrier/internal destruction Haki
This won't change anything where Luffy himself knows his limit he did say he only inflicted a superficial injury even with the boost of adv CoC.
But can we say it's on the same caliber as Togen totsuka from the scabbards ? We don't know but our scaling is based on Oden's feat which is far superior than KKG with Adv CoA .
adv.CoC directly into the face without any obstacles like God Thread and spiderweb inbetween.
I only believe what i see as i showed u the best feat of KKG with adv CoA as luffy implied is below heavy damage ( scars or something similar ) now with adv CoC the only thing we can see is Having an Oden level feat which is the bar minimum of a healthy Zoro and i repeat that feat is done by BROKEN BONES Ashura Zoro with < 10% OF STAMINA