I appreciate your post, but I would like to sound a note of caution and concern. It has been my experience that many times people have apparently false beliefs about abstractions that don't ground very well to observations in their daily lives but which they nonetheless use as (technically inadequate) justification for many pragmatically reasonable practices. If the abstract justification falls away, the justifications can sound hollow, and the practices can stop with negative real world consequences.

For example, your prayer practices (even if there is no god hearing your prayers) are intelligible as a kind of meditation on the moral, practical, and emotional aspects of a major decision with strong framing in terms of the outside view a hypothetical highly rational and benevolent agent would bring to bear on your decision. If you lack a justification for such practices outside of a belief in god you might stop doing them, even if they improve your life.

Or consider your younger (presumably less wise?) self that you wrote about:

I believed that living out a religious faith was the key to maintaining my sobriety.

What if, all those years ago, you retained that belief while dramatically and publicly shedding your belief in God? Do you think your sobriety would have been at greater risk or less risk? My guess is that it would have been at greater risk. Now consider that you may have years of accumulated "instrumental beliefs" that were previously justified by your faith and that may now weaken for an abstract reason that has nothing to do with the low level facts that probably were the real (subconscious) reasons you did things. And I know of several people whose romantic relationships fell apart when they changed their theological beliefs, creating an intellectual distance with their partner.

I wouldn't be surprised if you already understand many of these points, and I don't mean to cause offense with this but it seemed irresponsible to not raise some cautionary note. Unfortunately, I don't know of any resources to help people traverse the path you're facing in a series of small safe steps. Perhaps other people here could help with that though?

I hope things go well for you. You'll be in my thoughts.