Obviously I think it's fine for Zenos stans to like Zenos but I don't really get where people are coming from that "he didn't get the chance to shine." The guy was ostensibly the main antagonist of Stormblood and appeared in both sides of the story. The fact that he was overshadowed by Fordola and Yotsuyu isn't because he wasn't given any chances to stand out, it's because they're much stronger characters than him which made them completely overshadow the villain that was supposed to be the main threat. He's been around longer than almost any antagonist in the game, but probably has one of the weakest presences.

It's not like you can't do a lot with only a little amount of time either. I'm pretty sure someone already brought him up but at the end of the day Valens is just a much better executed version of Zenos' archetype: like Zenos he has absolutely no redeeming qualities, but his personality and actions make him way more hateable so that by the end of Werlyt you want soooooo bad to see this dude just get his teeth kicked in. Zenos actually does very few especially fucked up things on screen and despite his obsession with WoL, almost none of his actions are directly affecting towards WoL or his circle of friends (read: the main cast) to inspire any particular ire against him the way Valens does.

Don't get me wrong when Zenos inevitably bites it in Endwalker, I'll cheer. But it's not because I feel anything towards Zenos as a character; it's because I find Zenos as a narrative device to be incredibly obnoxious.