For me it also fails to account for something we came to know, i.e. that the souls inside Zodiark were in a kind of limbo. The Anamnesis scenes, which as you say are referred back to in the Q&A and therefore cannot be discounted, had her acknowledge the good intentions of the Convocation. That montage basically seems to focus on the most grief-struck of the ancients during the world still being on fire, so it's no surprise how they react to her, assuming it's accurate to what happened, but it's certainly not all of what happened. Had they shown something like Elidibus emerging and conveying the state of the souls inside Zodiark to the divided ancients (a division which she thought was important to avoid), quelling opposition to that final plan, with her followers only in very vague terms stating that their doom would repeat but not explaining why... yes, I think it'd undermine the effectiveness of that scene quite a bit in trying to justify her, which even so, I think it does not succeed in doing.
I think even in terms of the scope of it, he can't really be let off the hook, because the WoL had explained to them the events which would unfold, which by that point they'd realised would originate from outside Etheirys and which they concluded was dynamis-related. When Meteion reveals her "manifesto", it should be obvious that at a minimum that'd be the result. No matter how emotional his frame of mind, he still had agency at that point, although I think we're all agreed on that.
On whether Venat or Hermes is worse, I'd say it comes down to whether causing a problem or knowing about it but keeping it to yourself and unilaterally making a decision affecting all of mankind's ability to respond to that problem so that it adopts the "right" attitude to suffering is the worse of the two. They threw in the time loop to muddy the waters a bit with Venat, but it wasn't the reason she gave for constraining her actions the way she did, and if you read her actions through the lens Brinne pointed out (some romanticisation of the suffering she perceived in the sundered world), you can take issue with her for throwing the towel in for what were potentially ideological reasons. I'd still say he is the worse of the two for playing a causal role in it, but where I find her worse is less to do with her own actions and more to do with how the story essentially presents a character that is a fusion of Yunalesca from X and Venat from XII, but would have you think she's a Yuna, Aerith or Ashe. Even if the writers acknowledge that she's comparable to an Emet-Selch warped by a 12k year gruesome toil, the in-story representation of that is lacking, to say the least.