Another example being:
When Luffy gave the Order and parted ways with them, the manga had us focus on Zoro, and then proceeded to have Zoro pretty much order the rest of them to continue going, and they did despite being reluctant. Then Nami and Sanji (alongisde Zoro) proceeded to explain to Vivi that it was okay, much like how Sanji agreed with Zoro in last example. Zoro again took the initiative and actively commanded/ordered them.
Here, again, most if not all the Straw Hats are reluctant, and don’t really want to get involved during Yasuie’s execution- and it’s strategically bad anyhow. Zoro jumps in, tosses the kid to Sanji while telling him to take her- has the entire crew follow after him, then practically, again, orders Franky to cover him as he charged. Taking the direct initiative and command again.
Another one is how when Kuma appeared, Zoro actively ordered everyone to stay back, and they did.
There are several more examples, some smaller, some bigger- but it’s not just this. When it comes to decision that only Captain can have a say in, and the said Captain isn’t responsive, the crew turns to Zoro for it.
A prime example would be:
When Usopp tried to BS his way back into the crew and Chopper wanted him aboard, he first went to Luffy for the decision to grab him back, and when Luffy ignored it, he went to Zoro for the same thing.
Another thing is that Zoro is nearly always the one who keeps the Captain in check, making sure Luffy’s okay and that he doesn’t end up messing up. Other than the Usopp moment, some other examples would be:
After Usopp’s battle, Zoro making sure Luffy doesn’t end up with any issues of sorts, all while consoling him.
Or here as he keeps Luffy in check for being reckless in New World.
As far as the narrative perspective is concerned; Zoro has always been implied in the light of “Right Hand Man” or “First Mate” or “Vice Captain”, be it the opinion of other characters, him being compared to his Captain often, or his public reputation- or the running theme of him partaking in several narrative actions, both minor and major, like the writer choice of having him take Luffy’s fatigue over Sanji during Thriller Bark, having him be the one to explain to us readers what 3D2Y meant, and countless others.
I don’t think there’s an hierarchy within the crew, but if I have to come up with an unofficial one, in my opinion it’d be:
First Mate: Zoro
Second Mate and Strategist: Sanji
*Theory by Shanal183