Canon Ball tore through 4 or so Biscuit Soldiers, Tempura Udon would obliterate them.
I don't think you can change the trajectory. It's trajectory wasn't altered in the slightest here:
Tempura Udon is much more comparable to King Kong Gun than it is to Kong Gun.
The radius of the explosion is far too big for Kat to phase around it:
I don't think she gets oneshot, it's just that King can spam them endlessly, and which she'll have difficulty blocking (Zoro did and he's a significantly superior swordsman).
I agree with the spirit of this. At least that King would find it significantly harder to pick them off with Katakuri foreseeing all his incoming attacks, coordinating their response and running interference.
Awakening and Power Mochi may be able to interrupt King and e.g. cause a Tempura Udon to be fired off course.
I guess the main issue is that Cracker has no way to contribute offensively against King and Smoothie is of very limited use when King's Wind Scythes are faster and stronger than her slashes and he can spam them.
Only Katakuri would be able to consistently land any attacks on a Flying King.
And this is without getting to King's high base durability and his healing.
It'll turn into a battle of attrition and I think King will be dealing more damage per time.
Smoothie or Cracker will fall first and once that happens, it'll only get easier for King.