Zenos, without a doubt, no matter what happens in Endwalker he will always be a terribly written villain, because if it takes over 4 years of writing for your villain to have a narrative purpose they are a terribly written antagonist.

Yes Elidibus falls into this as well but guess what he at least at this point has a permanent send off and he actively played a part in manipulating the plot.

Zenos's last impact on the plot, killing his father and you can't say only Zenos could kill Varis especially giving Nerva and Varis's uncle, that happened over 2 years ago, 2 years of writing and still he has achieved nothing, every antag must fade, everything returns to boredom, everything else since then has all been Fandaniel's plan that Zenos has just gone with, Fandaniel is driving the plot forward into Endwalkers not Zenos.

The dude you are hyping up a boss fight with is not the dude driving the plot at all there is a problem.

Then there is Zenos's second major problem, he willingly died and came back against his wishes, this is never addressed, the man committed suicide yet this had no affect on him at all like it never happened, this then compounds the issue of why the hell should I care about beating up this man again, there is no stakes because if he comes back when he willingly killed himself why should I believe he will be permanently dead when I do it?

That second point is my biggest gripe with Zenos living atm, it ruins his last scene in 4.0 completely and taken all tension out of beating his butt again. I just don't care what happens to him I just want him gone from the story.

Nearly as much as G'raha's fanboying which is a trait I hope they either pull back on or just faze out completely.