No, Yamamoto having a different bankai was an early mistranslation of MS (the same guys that had Kenpachi wanting to rape quincies and Shinji talking about kong) propagated then in BA, what he says, and you can watch the episode 6 again if you want, is that he didn’t use his full power 1,000 years ago, and this episode gives the context behind it.
You need to go watch episode 6 again. The way "Yhwach" described it 1000 years ago is much different to what it is now. Yamamoto even asks him if he's sure that it's the same as last time. He evolved his bankai and it's different than what it was 1000 years ago.
We know bankai can change from Hitsugaya so it's not far-fetched.
Having blut vene is pretty much required, quincies use the spiritual power/reiatsu differently than shinigamies, it’s not their body that gets stronger inwardly, but their manipulation outwardly, unless specific cases connected to their schrifts, like James, Gerald, Driscoll etc. Yhwach’s being the Almighty, who doesn’t power up the body.
I know how quincies use reiryoku/reiatsu vs how shinigami's use it. I'm not saying Blut didn't exist, but in this case, it might have been turned off or he could've been using Blut Arterie since you can't use Arterie and Vene at the same time.
There are also clear limits to Orihime’s powers, resolve doesn’t magically solve the reiatsu difference between two people, like being unable to resurrect the Soul King (Yhwach himself calls her a mere human, and her resolve was pretty much the same, if not better considering the situation got worse)
I agree that Orihime's powers have limits, but the Yhwach situation is a bit different. Yhwach did have his Almight which would've prevented Orihime's abilities from even working on the Soul King.
The Ulquiorra situation she was literally panicking; I wouldn't call that a good mental state.
But that’s fine, I guess we can classify this as a feat for Choijiro, sneak attack or not, Bazz-B, Nanana and As Nodt tried the same but failed, you need some degree of skill and power to pull it off, otherwise someone like Soifon would go and oneshot everyone.
It's not a feat for Chojio. You don't give a feat for stabbing someone off guard because by that logic that laser gun that shot Goku is universal because it hurt him while off guard.
Bazz-B, Nanana, and As Nodt failed because of Yama's AOE damage, not because of reiatsu difference.
