Since you're such fans of Zoro maybe you should understand the character before sharing nonsense. Sanji doesn't live "rent free" in his head but they both care about each other a lot, and I don't even need to defend my opinion because Oda has made it blatantly obvious, to the point Zoro's
tsundere attitude has been explicitly stressed twice that I recall:
I mean, I know most of you aren't the brightest here (Finalbeta seems a bit more educated than your average cultist around here, at least), but it amazes me how easily you assume someone is a Sanji fan (which I'm not) as soon as they point out the, on the other hand, obvious way Oda writes these two relationship as your archetypical pair of frenemies.
If this ends up being the proper reading of the scene and Zoro was indeed saying he's looking forward the moment to kill Sanji, it's clear as day that he's just playing his "couldn't care less" facade that falls apart as soon as more emotional and empathetic people (Sanji and especially Luffy) see through it.
It's really funny, for real: pretty much everybody in-verse mocks at Zoro on his attitude towards Sanji (Nami treating him like a kid with the "t-then I'm like 2000 men!" moment, Luffy laughing at him since he notices with ease he's worried, etc.) but you guys take it as serious stuff? Am I missing something or are you really so unable to understand a drawn story for teens?
My "hadcanon" is just an interpretation of the scene. Zoro can do both, just like dumbasses where saying that Zoro wouldn't fight King because he had to kill Kaido as if those two were excluding. Zoro can defeat King, deal with Sanji's conflict if required and kill Kaido, and if the situation happens in which he has to decide between killing Sanji or Kaido I'm pretty convinced he will prefer to help a crewmate on his own request than slashing a bad guy he just met.