Good luck with your tough growing conditions. Gary from Palm Springs used to be here a lot. He is in a suburban house. In his back yard and more (of course!) Gary planted fruit trees (mostly mangos) close together. They reinforced each other to retain moisture and shaded each other. I think he had a high stone/concrete block wall helping his efforts. Enough to create a wet mini-oasis in his dry area of California. He created his own wetter micro-climate. He admitted as much to me directly about 8 years ago on this forum. I believe Simon is well acquainted with Gary.
The video of a tour of Dr Richard Cambell's mango-centric farm near Miami.
https://www.youtube.com/watch?v=YeCrZC_5slUHe has an upper canopy of fast growing non-fruit trees that shade the fruit trees below. I think this would be a good approach in your so called hellscapes. Plant these "nurse" canopy trees to protect your young fruit trees. At a certain point when your orchard is established. When the fruit trees are mature enough to shade each other and become sun-resistant. Then you cut down all or some of these upper canopy trees. Or maybe cut their height in half.______ Perhaps inter planting banana stalks will shade young fruit trees enough. Moringa perhaps?
Also I have seen photos of the large organic Keitt mango orchard in California. It was a few years ago but if iirc it was a three acre orchard out in the middle of nowhere. Nowhere meaning there was just bare dry, barely vegetated land surrounding it on all sides with some foothills rising in the distance. Find this guy, visit his farm and ask him how he established his Keitt orchard. Being organic and all he can probably name his Keitt selling price. As in how many large mango orchards are there in California? One? Two? Five? Cannot be more than five.
I am open to correction on any of the above__