Uhhh...

On release I am inclined to say that Stormblood was the best. It felt rewarding to do whatever it was that you wanted to do.

I liked HW also, it required effort, it too felt rewarding, e.g., crafting first set of Ironworks gear. Neo Aetherstones bred an absurd amount of life into doing Coils unsync... But granted, some of it was because some systems were a little clunky,

Shadowbringers, Endwalker and Dawntrail have all felt like expansions where they've just been giving tokenisms to players for things they ripped away from said players... Rewarding manual crafts, and a reason to actually learn the crafting system? Expert recipes, and even then, they don't feel core, and nor do they hold a candle to systems like WWYW.