Oda keeps stalling with Sanji's arc fight. I'm fine with most things so long as Sanji gets that Calamity fight first. Just like how CP0 hasn't gone after Robin, they'll wait for pirates to start dropping before going after Momo (in my opinion). To me, it would make the most sense for King to go after Momo or send Queen after him since killing Momo was one of the Beast Pirates'major objectives but all the Flying Six are busy. We'll see in the coming chapters.