Sanji's pride doesn't allow him to use the Newkama kenpo techniques he learned with ivankov. We have yet to se sanji use a newkama kenpo technique after the time skip right? Could it be that his pride doesn't allow him use them kinda like the raid suit thing. Sanji has yet to be pushed to his limit in after the Time skip, atleast not like he was with his battle with jabra or like luffy was when he fought katakuri. if he fights one of the calamities, which he most likely will we might get to see sanji swallow his pride and whip out some death wink type move lol