You have twisted several things here to fit your argument but it isnt like that at all.
Last fight shows no durability feats when you faint after getting hit and stab. Luffy got stab and he kept fighting Katakuri to the end and didn't faint and his was more damaging into his ribs compare to an shoulder stab. He does need to as he wouldn't have say that just because he isn't careful enough. If Luffy, Sanji, and others are training up for major powerups, Zoro will do so not to be left behind in the end.
What last fight shows is that Zoro was seriously injured
because of a cheap shot. Name one injury that is even close to this which wasnt a cheap shot and not voluntarily taking Mihawk's slice and Kuma's bubble. Zoro's defense is rock solid, he never takes serious damage in a fair fight, you conveniently ignore the cheap shot here.
Luffy had more plot armor in the fight with Katakuri than all other characters in the series
combined. I told you, enjoy the show, you will see that Zoro wont retrain anything, he trained more than any other Strawhat and still has only shown a fraction of his power. Who else, aside from Luffy, is training?
What ya mean? It can prevent that as Luffy's showcase he can deflect sharp weapons like blades from cutting and piercing his body (Unless his opponent's Haki is stronger in that point or he didn't put too much effort in it). Kamazou is someone who looks to be Headliner lvl with no such of Haki to do that. Your looking wrong areas as others have question it on Orojackson, Reddit, Youtube, etc.. Hunger was never it. Oda would have stated that forwardly over something as simple as that. He isn't Luffy btw, hunger wouldn't be that downgrade to him unlike Luffy.
Haki only protected Luffy from sharp objects against fodder while against serious opponents it always failed. You have an idea in your head that Zoro should have used CoA on his body to protect himself from Kamazou's blade and Hawkins' nails but only you think that would actually work. It would be no protection and I told you back then when you liked nails more than faint that Zoro will never use CoA on his body and only on his swords since it serves no purpose, you dont understand Zoro and you dont understand CoA.
I looked in right areas, it's just you being unable to tell apart trolling and people actually doubting Zoro's endurance. Nobody doubts it.
That's more your reason than true fact. So far if it was hunger, Oda would have said something about it otherwise or Zoro comment about it. He face many threats without eating prior and still win or lose due to something else. He isn't like Luffy who like that if he is hungry. I do understand the fight, but he clearly went down out of it pain not because he thinks Gyukimaru was harmless since he saw him taking an weapon. Why drop your guard with someone who JUST took your sword. He could have took his other blades too since he is an weapon collector. Zoro maybe dumb at times, but that is stupid to do and doesn't make sense on his character who value weapons. He was knockout plain and simple. Nothing hints on him losing because of poison, hunger, etc.. All excuses, and you ned to understand that Zoro isn't same as pre-timeskip in durablity as clealry Oda knew what he was doing when he did this.
Reason for fainting is obviously plot armor, to get him into bed with Hiyori. The one and only justification of the faint that we actually got in manga is hunger, lame reason to serve plot purpose but it is the only thing provided in the manga, you are ignoring this.
He went down out of pain? Where does the manga confirm that? Provide evidence with a screenshot.
You are ignoring that Zoro saw Gyukimaru turning his back to him and leaving. Why drop the guard with someone who took your sword and
was leaving? For the plot purpose, to get him into bed with Hiyori.
He wasn't knocked out, plain and simple, look up the definition of a knockout. You cant kill Kamazou while being knocked out or can you?
First, he didnt lose, second, yes the manga actually hints that he fainted due to the hunger, look it up in the manga instead of using your headcanon.
There are no excuses, just you ignoring facts from the manga, like you usually do because it fits your argument.
What you need to understand is that durability doesnt work like you think it does and Zoro is far stronger than pre-TS in every aspect, durability included.