More random thoughts -
Observe carefully how Mother Nature grows things in the desert. She is the master gardener, the rest of us are amateurs.
Inventory of the four elements in the Sonoran desert basin -
Sun - too much of a good thing. Dries out plants, dries out the soil. Over-intense sunlight can actually shut down photosynthesis during the heat of the day.
Water - too scarce.
Wind - Assists the Sun in driving the water from the earth, and from plants. Wind is a powerful dessicating agent in the desert.
Earth - tending towards alkaline, compacted, poor in organic matter. Does a poor job of holding water.
So, the soil needs mulch both to protect from sun and wind so it will retain more water, to provide organic "sponge" to retain water, to buffer the alkaline soil and provide fertility.
Much of the life in the desert lives under low trees with umbrella-like growth habits, such as mesquite and palo verde. These trees provide
shelter from sun and wind, their leaf-drop provides the much needed mulch. Their
roots help open up the soil to increase infiltration of water.
It would be wise to emulate that in your garden, providing as much filtered shade as possible for the plants, with oodles of mulch underneath. It would also be good to identify the direction of the prevailing wind and establish windbreaks as necessary.
If you like raised beds, go for it. I think that sometimes raised beds are like tilling; We do it out of habit without really examining whether circumstances require it. In a desert setting where plants need protection from sun and wind, putting them in a raised bed that is elevated up into the sun and wind seems counterintuitive to me. I would think that this would be setting better situated to Zuni waffle beds or mulch basins, where the plants are actually a little lower, and sheltered a wee bit by the surrounding soil from the sun and wind.
There is also the fact that raised beds are raised, whereas water seeks the low spots. So runoff into a raised bed is unlikely. Creating low spots for planting OTOH can be water-wise.
Trees also can be water harvesting structures.
One day I was driving on the plains of northern New Mexico in a dense fog. Sabino, juniper, was growing everywhere, and I soon noticed that there was a circle of wetness beneath each juniper. The leaves were harvesting the condensation and dripping it on to the
root zone beneath each tree. The leaves were positioned and shaped presumably just right to do so. Trees know how to be trees.