If Zoro isn't forced to use Asura on King while Sanji goes all out then it's really not that.
Other than that, why are you debating over head-canon. We don't even know if Zoro fights King or not- and even if he does, we don't know how it'll turn out lol.
Anyhow, I'm not debating whether Zoro > Sanji or not- you already admit. I'm just saying from the portrayal and narrative thus far in story, Zoro > Sanji with combat gap being clear-cut but not massive or anything. Again, for the 100th time, just like Rayleigh and Gaban; the biggest parallel.
And in terms of importance to Luffy, Zoro, again is > Sanji.
Zoro and Sanji are the two biggest pillars of support for Luffy, and they were the last men standing against Kuma; his right and left hand men. But the one who took Luffy's pain at the end was Zoro- not them sharing it together. Thus cementing Zoro's place as the undisputed biggest pillar. That's incredibly clear-cut parallel; and it doesn't take anything away from wings. Wings simply cements them being his two main men.
Also, VC straight up calls Zoro as someone who acts like Luffy and crew's First Mate.