One does not lose faith, one re-discovers one’s own agency.
American Christianity to my young mind was little more than a social club.
And then I traveled the world.
I came to know Godhead through the line of Mahadeva. That is to say, India and Shiva revealed to me something of the human spirit and how we as Man relate to God.
In the decades since, I have reformulated these conceptions without the dressings of any particular religion, Hinduism for instance.
Here is the divine order as I have come to account:
Supreme Divine Aspect
Totality of All
Universal Potential
Godhead
Manifest form
Truth
Emergent being
Self
I think the atheist and those of spiritual ascent may both agree that “universal potential” and “Godhead” may be synonymous, and find some common ground.
As for what face or story or interpretation of Godhead one comes to recognize or conceptualize I like to say that is it not Godhead who is the deceiver, rather Man who deceives himself.
Existence is divine. What one makes of it is one’s own path.
The terrible burden of free will is that existence is savage, and one must “chasten” their God, for they love their God, and they must perish by the wrath of their God (to paraphrase Nietzsche's Zarathustra.)
I do not have faith. I am one of principles and devotion.
Christianity, and / or the stories I was told via either Sunday School or other interactions with religious folks, never made any sense to me. It all sounded like fiction. It didn't match my sense of 'the world'.
So I never really lost faith, I never really had it in the first place, but any attempts to convince me into the fold didn't feel like they were describing reality.
Someone once attempted to recruit me into selling Amway (a pyramid scheme / Multi-Level Marketing scam, like Herbalife), and it felt similarly creepy to the way some religious folks have tried to describe their faith to me. That spidey-sense feeling that something is off.
Don't get me wrong, there are good people who consider themselves religious, but they seem to be the more 'casual believers'. A friend of mine has basically said that they literally enjoy the community, with the implication that the actual 'belief' part is incidental and matters far less. This kinda fits with my belief that religious organisations are a good thing if they're providing a service to those who need it; and there are plenty of people that need community and acceptance.
I spent most of the time from my mid-teens (give or take a bit) to sometime in my 30's referring to myself as agnostic or maybe "weak atheist" since I can't prove there is no deity / deities. And a very slight thought that there was some merit to the "irreducible complexity" argument also weighed on that. Then I read Dawkins' The Selfish Gene and that satisfied me that the "irreducible complexity" argument doesn't hold up. Since then I've generally referred to myself as an atheist if asked about my religious beliefs. In some contexts I might say "non believer" or just defer from answering, to avoid starting arguments.
Then studying various other religions.
Then studying human evolutionary psychology and paleontology, as well as various regional histories.
Then it all made a LOT more sense.
That said, have really enjoyed most of the humanist aspects of the Pope Leo AI Encyclical and also enjoyed Francis' AI essay, and I am coming to understand the perspective of those who value religious-sourced narrative for its philosophical posture. These narratives are evolving as human understanding evolves, still with lots of ridiculous contradictions (prohibition of abortion among the most blatant), but there is depth of thought around valuing humans and human work and so forth that is a pleasant contrast to the predatory power hungry totalitarian selfish nihilism of most AI/tech and political leadership.