Adobe brick in Arizona accessory dwelling unit, partially underground

I live in the low desert of Arizona and would like to build a guest house / small house on my property. I want it to be made of as much natural materials as possible and to use as little energy to heat and cool as possible. I was thinking of trying to dig down at least 4 feet or so into the ground to use as a thermal buffer to keep it cooler in the summer and warmer in the winter. Assuming I do not hace caliche in the top 4 or more feet of soil, are there other considerations I am not thinking of? I was wanting to use the mycelium insulation panels I have read about on here. I’m already growing my own mushrooms so I can start growing them in a mould.

I was also thinking of starting with a cheap metal frame and building the brick around it which I think would keep any wood used for framing away from the soil to prevent termites. Does that sound like an unnecessary step? Does anyone know anyone who has done dug in buildings in Arizona that I may consult with ? Any input is greatly appreciated.

What is this please?

hace caliche

I work on a principle that nothing is 'cheap', its good value!
Can you get wood that termites dont bother.
I work with adobe and it would be an excellent form of clay to use.
It only consumes labour.
Do you have water issues around the build site?

Caliche is cemented rock, carbonate minerals  like limestone and dolomite.

I sketched out an invention for a possible way to remove caliche… which is funny because I live far away in Massachusetts. No caliche here. : )

Here in Texas, caliche is a common road base material.

It is ground-up limestone aka calcium carbonate and forms an almost cement-like surface.

According to this post:

Bryant Redhawk said, "The most organic method of decomposing Caliche is to use vinegars, Caliche is Calcium carbonate and vinegar will dissolve it just as it does in high school chemistry class. (Remember the rock that bubbled when vinegar was poured on it?)

https://permies.com/t/74432/Sunken-beds-hardpan-caliche

I am a masonry contractor, give me a call. Touch and hold a clip to pin it. Unpinned clips will be deleted after 1 hour. 928 595 2703

Hi John, Yes I love your perspective on building. I would like to (help) build something that will last a very long time. You write like your writing a poem! For some reason I always drop a typo when I'm saying I have something and so I'm constantly hacing things. Thank you to those that replied about the caliche. I do not have water issues around the property, aside from some building up of a few small areas that I need to do. I would very much like to use adobe. To Carson - I apologize for the late reply. I do not know how to do what you are asking of me as far as touching and holding a pin, but I will send you a text message and see if we can get a conversation going. Thank you very much for your responses everyone.

Super Adobe domes
https://www.calearth.org/intro-superadobe