Let's break down your post bro
Khalifa got Sanji to half health... Even if this were true, it's not as good of a look for your boy as you think it is. Sanji having an easier time is highly debatable, he couldn't even do any meaningful damage before DJ.
Zoro remained full health while fighting Jabra and Kaku... If this is true then it's an astronomically better feat than sanji getting the shit kicked out of him by nami's opponent, someone who should be worlds below him at that point.
He was the most proficient tekkai user in CP9, that doesn't necessarily mean his was the strongest but for the sake of argument, fine, let's give it to him. It means nothing because DJ is a hard counter to it. Basically makes it null and void.
Except despite jabras words... jabras actions showed that sanji was damaging him.
This is a fact. Reread the fight. He went from talking shit to being scared of sanjis attacks and running.
Sanji mentions that his attacks are finally working.
Etc... I can list more evidence or the panels. Just ask.
Being nerfed to half health is impressive. Khalifa is a female. His one weakness. It is impressive. Tell my why it's not. Please.
Zoro blocked the non serious kaku and jabra using his swords. Not his body. Zoro wasn't tanking the attacks. Sanji was. Sanji ate the attacks like a boss.
The tekkai technique wasn't mentioned to support him as being stronger. No.
I mentioned his tekkai to dismiss any ap arguments that could be made. Sanji had the hardest barrier to overcome ap wise. Jabra being the most proficient... essentially solidified my position of jabra being a narrative device. A device that portrays him as much a challenge to zoro as to sanji. And vice versa for kaku.
Diable jambe and sanjis physical strength is indeed a great counter that nullifies the tekkai. It's pretty crazy how rokushiki mirrors haki to the T. It even has an advanced coa parralel with the king gun technique.
On a side note. Please tell me your opinion. Do you think coa protects from diable jambe? Considering the haki/rokushiki parralels and sanjis initial usage of diable jambe.