King would have to sacrifice that very same defense just to stand a chance at matching Katakuri’s speed. So his defense is irrelevant, and Katakuri can spam dozens of attacks at him at any given moment, which will wear King down pretty quickly if he’s giving up durability for speed.
And King still hasn’t shown any real reliable counters to FS, this speed increase would likely still not matter too much against Kuri.
Those portals are Power Mochi (>= EG). And Katakuri hasn't created them randomnly out of the air anywhere afaik, he just creates them around his vicinity.
Tankyudon is a hybrid move, yes.
Zoro never dodged a Tankyudon though. He tried to counter it with Ul Tora Gari and got yeeted out of the Skulldome.
That's Katakuri's max evasion speed. I'm talking about your scenario bro, Katakuri fighting King for days on end - you really think King won't land 5-10 Tankyudons over multiple days? Future Sight will wear down faster than King wears down though.
Katakuri is the one with the gimmick. Katakuri gimmick trick this opponents into thinking he is invincible. Luffy was attacking him and he thought that his haki attacks had no effect on him and Katakuri can't be hurt. In reality, Katakuri was just moving his body around Luffy's attacks.l
King is a fighter with incredible durability and speed. His flames allows in the switch between even greater speed beyond characters like Katakuri and Marco or greater durability/defense beyond Kaido.
Sanji and Zoro seems now the strongest left and right hands of an Emperor out there (minus the Shanks crew which lives of pure hype for now).
At the moment it's difficult to think about Burgess and Shiryu as real threats for them honestly.
Maybe only a huge awakening of the Suke Suke + CoC for Shiryu and a crazy powerful mythical Devil Fruit for Burgess can do the trick.