The dough is very crumbly even after sitting in the fridge overnight. How can I save this batter?

Meant to suggest that flour naturally can have varying degrees of moisture and/or that dry atmosphere where it is store may remove some (more) moisture from the flour on hand.
Either way, you might need more water/liquid than the original recipe called for.
I hope you were able to fix the crumbly-textured dough.

Thanks! That helped!