It’s the Sanji Blackbeard matchup that makes by far the most sense to me.
I find all the other connections people make for him tenuous, whether it’s to Lafitte, Burgess, Shot.
If there isn’t a Blackbeard cook- and there doesn’t seem to be one- then North Blue royalty is a concrete connection between the two, especially given that it’s been so focused on for Sanji in the last few years.