I wish they never explained Vecna's motivations.
I'm rewatching the brilliant Fargo series once again, and the character of Lorne Malvo is one of the most mesmerizing, terrifying creations ever put on television. He has this mythical quality about him that comes from writer Noah Hawley's staunch refusal to over-explain the character's twisted, nihilistic worldview. Malvo goes on a few tangents here and there about the world not really having rules and living like a "lone wolf" but these are intended more as vignettes peering into his soul (insofar as he has one) rather than "explanations" of how he came to be.
It made me think of Vecna, who was also this frighteningly nihilistic, single-minded killer (with an actual mythical element involved as well)... until they gave him that ham-fisted edgelord monologue about his parents, and spiders, and "humans being a pestilence on our ecosystem" and whatnot. Sure, it gave Jamie Campbell Bower a hell of a showcase, but I felt it made the Vecna character (and the show at large) a lot less interesting and intelligent.
For one there was the wooden dialogue, which sounded like it was written by a high schooler who discovered antinatalism on the internet, and which no actor can really salvage. But worse, it tried to cram ideas and themes that really required a longer exploration (his social ostracism and brewing resentment towards his family) into a single barrage of exposition, which made his backstory feel undercooked, unconvincing, and ultimately unnecessary. I enjoyed the twist that he was 001, but Vecna was a lot scarier as a ghoulish, unfeeling, "senseless" killer - a human manifestation of the Upside Down's abstract and impersonal evil. With the path they instead took, his rage is absolutely palpable, but not as convincing or well-founded as it should be. And the reveal that he has puppeteered the Upside Down all along exacerbates this problem.