You may have as many frustrations as you like, but frustrations are extremely lousy compasses towards finding out the truth about existence.
The real truth is that only human beings have a need for "God". No plants or animals could care less. So we have invented "God" for the world to make sense to us. Because we are ultimately narcissistic creatures who hate to think that we are not "important" and "valuable" to smoebody else, whoever this may be.
The truth is also that it is precisely the people who find it hard to relate to other human beings who seem to "need God" the most and show the most "frustration".
This is why Ahura Mazda is the opposite to the concept of "God".
Zarathushtra realised that human beings are to provide each other with meaning and love, NOT an external God to replace human beings. This is why Ahura Mazda is NOT an ersatz Father for the lousy fathers among us, and no ersatz mother either.
Instead, Ahura Mazda is when human beings get together and use their minds to create a world for themselves, a civilisation. The universe is Ahura, but Ahura Mazda is the mind WITHIN this universe.
Searching for a God outside of the universe is not only meaningless in the sense that you will never find this God any more than children find Santa Claus on Greenland, it also ultimately leaves you with the necessary idea that God is superior to The Universe.
And then you're back in the same boat with the Muslims and the Christians who hate this world and wait for something superior. Which again is the exact opposite of Mazayasna.
Physical reality is immanent, mind is transcendent (albeit not transcendental). Ahura is immanence and Mazda is transcendence. Zarathushtra knew this already 3,700 years ago. Western culture did not realise this until Immanuel Kant in the 18th century. When can we please stop retarding our beautiful and wise religion into an illogical and unfounded Islam-Light, OK?
And it is precisely when you can only base our beliefs on literal readings of poetic verses from The Gathas that the faith loses all credibility. This is just turning Mazdaysna into another stupid superstition among others. Belief without mind is not Mazdayasna. Gathas verses read literally in opposition to modern science are useless, even to Zarathushtra himself.
You express a view (and frustrations) that I share regarding the belief that "God" has no reality outside of the physical universe. And, as I have said before, if the physical universe is all there is, then where is the need for "God". Where does "God" come into the picture. In this respect, you have expressed my view much better than I have done. My sincere respect and admiration.
But your argument is valid only against the kind of 'pantheism' that believes that "God" has no existence outside of the physical universe. Like you, I do not see that kind of belief in the Gathas.
The immanence that I see implied in the Gathas and some later texts does not limit the existence of Ahura Mazda to the physical universe. As I understand the Gathas, the physical existence is a temporary experience to enable the perfecting process.
So what existence is there outside of this physical one? Zarathushtra is so honest, that he does not specifically address the subject of the after life (i.e. of life or existence after death). But in 1,001 subtle and beautiful ways, he implies that there is indeed an existence after this one existence that we experience on earth.
If you believe that there is an afterlife, then, so far as humans are concerned, we have a physical existence, and also an existence that is not limited to the physical. While we are alive, in this physical r eality, we are a part of it, we are integrated with it, but we are not limited to it -- there is more to us than our physical reality. In the same way, Mazda, as part of the life force that we all share, is a part of the physical reality, but not limited to it. There is more to Mazda than the physical realilty. That is what I see implied in the Gathas and in some later texts.
Wishing us the best,
Dina G. McIntyre