Making this post of my realization after I finished both Sunken Temple of Qarn dungeon & Primal Titan.

Both content should available back then in beta because from how you play those 2, this will fully test out not only latency issues, but also quality of your service provider and thus making more informative decision of your server region choice.

Not trying to spoil too much, the Titan battle are more punishing than Ifrit and the way it makes players who died can't be raised. And the temple itself requires players to constantly dodging to avoid deadly attack and status. Even Brayflox which is beta's highest dungeon available, are in my opinion, not doing justice enough for a challenge to see how your connection quality performs.

I know this is kinda too late now, but hopefully this help current players to realize if their choice of server are meant to be.