I think the Eorzea Time is tied to the server so it probably just isn't possible to allow some players to adjust the time to how they want it (so locally). Also it needs to consider that not everyone will be in the same time zone to begin with, like the NA worlds have players from all over the globe. Having Eorzea time the way it is, every player can get to experience night and day in-game without having to wait for it to happen in-sync with Earth hours.

Personally I don't need this change and my sleeping pattern works just fine as it has for the many years this game has been going, so it may just be you OP who that has sleeping issues.