Yeah, I'm putting Yamato vs either Jack or Smoothie (when she shows up LOL)
Oda can plot "daughter of Yonko Kaido vs Daughter of Yonko Big Mom"
However, with Jack.... I have this theory that Jack is in LOVE with Yamato
I feel that both are around the SAME AGE... and I could write a plot between them that Yamato ALWAYS rejected Jack who showed sign of interest towards Yamato... and I feel part of why Jack is like a GOOD BOY towards Kaido most of the time is because of his affection to Yamato... I feel he both, idolizes Kaido and has a soft spot for Yamato
So, if that is in anyway close to the truth, Jack might face Yamato..
But I have big feeling that it will end as:
Yamato vs Smoothie
Yamato inherited some toughness from her father
I wonder if Smoothie is the same, maybe she inherited a tough body like her mom. And that's what makes her Commander level