Agnostic spirituality does not claim knowledge of the supernatural. It is one of the three types of spirituality within the Material-Spiritual Framework.
You have things you believe and things you do not. Your agnostic positions sit in the middle. But Agnostic Spirituality is something a little different. It is not merely uncertainty about one claim. It is a type of spiritual system.
A system that still explores the things bigger than the self: meaning, mystery, connection, consciousness, death, the universe, and whatever else might sit beyond the edges of what we currently know. But it stays anchored to the material world. Claims beyond the material world may be explored, imagined, questioned, and taken seriously as possibilities. They are simply not promoted into truth.
Each speculative claim is then approached through either an explorative or apathetic agnostic lens. Interesting claims may invite explorative agnosticism. You look closer. You wonder. You follow the reasoning as far as it responsibly goes. But you keep one foot planted firmly in reality. Other claims may simply not matter enough to pursue. Those are viewed through apathetic agnosticism and allowed to drift away unanswered. This is not indecision. It is disciplined uncertainty. It is the willingness to explore without pretending the mystery has already been solved.
Within the Material-Spiritual Framework, Secular Spirituality is a form of Agnostic Spirituality rooted entirely in the material world.