Not to mention, Kakashi has never, ever used the 1st Gate in combat as far as I know. So, like, if he didn't use it against Pain, Madara, Obito, Kaguya, etc; I honestly >don't see why he'd use it against Isshiki in some hypothetical match-up.
Idk, seems really flimsy considering how massive of a jump it is IMO. I highly, highly doubt this is even something that Ikemoto/Kishimoto are keeping in mind at this >point. Kishimoto, espeically, given that it's something he never brought back outside of that one scan.
So I feel like it's pretty iffy to say that they had said amp in mind when they made the statements about NaruSasu being above him considering it's just not something >he uses in combat.
And even if we were to entertain this hypothetical, it's not like the temporary burst of speed would allow Kakashi to beat Isshiki anyway given the massive AP >advantage and the fact that it won't last for any significant stretch of time.