I guess There is a difference between learning advance kkg abilties like rotation and innate kkg abilties like byakugan and sharingan awakening.
However if the kkg byakugan is what is required of gentle fist taijutsu Boruto wouldn't have been taught it. Yes he's half Hyuuga but his mother being half Hyuuga doesn't mean he was guaranteed to unlock the byakugan or be capable of what you call a kkg
As i've said before, Originally boruto and Himawari were supposed to have the byakugan from the start, Kishi stated himself he forgot to draw them with it.
So the point of it not being guaranteed it mute.
Byakugan isn't stated to be required for most known GF techniques, It's there just as an aid, I'll say it again, The only technique that is outright stated to require the byakugan is Twin lion fists.
The rest just just say the byakugan is used to Aid the use of said technique, Using it at a scope to aim Airpalm or Using 360 to perceive attacks so you can use rotation to defend against attacks which would normally blindside people.
Because they are part of the suite of techniques that "use" Byakugan (altough you don't really need it for these 2). Again, Vacuum Palm is a technique that expells compressed air to a target's vitals. If you say that part of the actual technique is to hit vitals, and uses the byakugan to pinpoint the vitals, then yeah, you can say its a KG, but in the end, it's just compressed air. Gai with Hirudora could already do something like that (in a massive scale while we're at it), and that's no KG whatsoever. Same for Kaiten: unless it's stated somewhere that you need Hyuuga blood or Byakugan to expel chakra from every tenketsu, it's just that. Again, Gai when he opened the 6th gate against Kisame underwater, he did something similar (by expelling chakra from his entire body to push away a lake-worth of water out of his path), and that's no KG either.
It doesn't work like that.
It's like saying an uchiha using the sharingan to aid them in shuriken jutsu or anyother weapon based technique suddenly makes that shuriken jutsu/weapon based technique a KKG ability. Which it doesn't.
It's exactly the same for Airpalm/Rotation, Byakugan plays zero part in the actual mechanics of the Jutsu, It's just an aid.
It's stated you need hyuga blood when it was labeled a KKG, The only GF technique we know of that requires the byakugan is twin lion fists which is outrightly stated in it's DB.
Gai did do something similar but obviously different as labeled by kishi.
The more we learn about the hyuga in boruto (if at all) these things will make more sense.