They weren't done with Zenos at that point. Thordan was a one and done. I still think Zenos as a character still isn't done yet. Most of Endwalker is Zenos reflecting on himself. They've had the Zodiark story arc planned out for a while.

Stormblood overall was the weakest expansion XIV has ever had IMO. It made Shadowbringers that much better by Stormblood being weak.

You know Thordan is done because he turned into pure Aether.

Zenos does not and because he is a Resonant, he cannot truly die unless they use weapons similar in potency to kill Ascians which the WoL specifically does not use in this rematch.

He will be back I think.

I also hope they use Meteion more in the future since the original Meteion survived. Or implies that they do. Very much like the character.