The last official statement on the matter as far as I recall, earlier this year.

https://na.finalfantasyxiv.com/lodes...837.1597828932

> Launching of Data Center Travel System
> As I previously mentioned in a Live Letter, while the system has been designed to allow cross-region travel, we'll be limiting it to travel between logical data centers within a physical data center at first due in part to differences in game economy and values.
> We’ll be paying keen attention to the opinions of players as we consider whether or not to introduce cross-region travel in the future.