The thing is that once Oda is done introducing a new ability he doesn't focus much on it afterward. This even applied to base observation (who still very useful in a fight as seen in Skypea) where Oda emphasized that Luffy was using it in fishman island
But never made any mention of it afterwards til his fight against Katakuri. Like I don't remember it being mentioned in the fight against Doffy even though it's fair to assume he was using it.
One of the "issue" with One Piece powerscaling is that Oda isn't as autistic with his power system as other shonen authors where they make fights and the abilities used in them extremely explicit. What ultimately matters is how Oda wants readers to see the fights/power dynamics. You're not supposed to see Luffy as being nerfed from using whatever ability, but that his current base/G2 is simply not good enough against a old legend like Gaban, hence why he turns G5 out of frustration at the end and you even got Zoro jumping in.