aqwsed-The term “mystery” does not imply that all interpretations are equally valid or that our efforts to understand are in vain. Rather, it means that the reality being described—the inner life of the triune God—is ultimately above the full grasp of finite human reason, though not contrary to reason.
I completely agree. And they are most certainly not in vain when a sincere heart is searching for a clearer understanding. This is why it isn't damnation for the soul that accepts the Father and the Son as beings not of the Trinity doctrine. Although it may be central to theology, the doctrine is clearly not central to salvation.
I do believe that the doctrine in some ways does enhance our awe, respect and even love for our God. In addition to that it is a fascinating study into this mystery.
But it was God after all that used the very simple terms (knowing how human beings would relate to those terms) of father and son to help us understand him better.