That G3 scene wasn’t luffy matching Kata AP. Kata just gets shock, luffy picked up on his attacks(learning FS). He an immediately counterattacks kicking him away. When already saw Kata while trolling could casually overwhelm G3 with his base. So an attack obviously superior clearly not G3 lvl.
Hell it’s even further confirmed by Kata base AP with CoA, overpowering Snakeman AP directly. Which itself G3+, it’s random to think Kata physically abilities > awakening.
Kata AP definitely suffers from the luffy endurance conundrum.
That troll attack wasnt something that was natural though, he didnt overwhelm him immediately as well. It took a some time before that troll G3 overpowered Luffy's G3.
At best you can say Power Mochi is slightly stronger than EG. If the EG wasnt there, Power Mochi wouldve directly impacted on Luffy there, it wasnt gonna be boosted anymore in AP by any other mechanism. And PM was never shown to be G4 lvl or anything, in fact being able to spam so many G4 lvl attacks is broken as fuck. Definitely not the case.
Also Kata base AP never overpowered Snakeman IIRC, it was Block Mochi again which has superior armament. I maybe wrong though need to check scans.
Imo, his AP is underrated but it is not G4 level at all. At best, Zangiri Mochi was paralleled with King Cobra.