They wont.Endwalker is the end of the ascian story.If they had another calamity it would mean that 7.0 would still have the existance of ascians in some form which we know is not the direction they are headed.
They have too many other potential stories to go down in the ff14 universe in the source.
For example there is no hints towards tiamat being brought into 6.0
She's still alive trapped by her own will.6.0 now looks like 100% we wont go to Meracydia which has lots of potential for a heavy tie in to story with tiamat and a whole new saga.