What do you do against the high dehydration in the salt flats?
After you complete the first outpost, which is located nearer the edge of the salt flats, and bring the shard back to the guide, you’ll get to craft the water ring, which would slow dehydration.
You can also find some blocked springs around the flats as well as unlocking sigil gates (bring acorns and wood!).
A few sure sigil gates are located at the light houses.
Hope this helps!