Hermes and Zenos in relation to one another are so interesting in a way that leaves Venat completely out of the thematic spectrum, hilariously. Hermes's fundamental problem - both its origin point and his choice to continue wallowing in it until it broke him into something steeped in poison - was isolation. He believed he was isolated, and his attachment to his self-image as The Only One Struggling With Empathy meant that he, subconsciously or otherwise, kept himself isolated, which cycled into his despair and led him to viewing his society and world with contempt that eventually spiraled out of control. Emet makes some (clumsy, admittedly) attempts to reach a hand out to him in Elpis, but Hermes reacts with raw hostility, because on some level, he doesn't want help from people who "don't get it," so to speak.
Zenos is positioned in a similar way - the difference is, while Zenos is also a thoroughly Terrible person, he recognizes his struggle with isolation and rejection from the person he longs to connect with and is willing to re-evaluate himself and his approach, and then start to do the work to amend them. He doesn't fundamentally change himself - he's Zenos through and through to the end, callous war criminal extraordinaire - but he learns, after genuine self-reflection without the accompanying agenda of wallowing in self-pity, to better meet the WoL on their own terms. He recognizes that while there are vast areas of the WoL's person that he will never understand and honestly isn't interested in understanding. He will never "get it," but that doesn't mean he can't recognize them and support them in his own, deadpan dragon sort of way. Zenos, of all people, learns to actually connect with another human being, and this revelation ultimately saves the universe. It's the lesson that Hermes never figured out, even as Meteion worries about him until the end, hoping desperately for his happiness.
Fundamentally, Hermes's speech to the fire wolf was very telling. His empathy and pain at having to put the creature down was sincere and real, but he urges it to "hate, if it be your wont - we are not undeserving" specifically. Hermes is distraught over the way the creations are discarded in large part because he projects himself onto them. And deep down, he has begun to hate. Zenos, for all his massive, massive flaws and crimes, does not actually hate. He'll murder you and look down upon you, but he doesn't hate you. He is driven by love, as twisted and weird and unsettling as it might be, and there is a sincerity in it that allowed him to self-reflect, have an epiphany, and then transform into a giant space dragon after eating a big rock.
In that way, love, support, and connections emerge as the answer to despair, not engineering an environment of suffering to force people through until they just get used to living through it. (Well, a few of them, anyway. Most of them probably just die but, yes, anyway, light everlasting and all that.) That's my story and I'm sticking to it!
There really is some fantastic stuff in Endwalker, I think. I really do. Just, Venat and her albatross of "we must establish she is Likable and a Good Person at all costs." Oof. (Not going to lie, it's maybe a breath of fresh air to talk about the things I actually loved about Endwalker? Maybe the wrong thread, though, so excuse me for the weird tangent!)