Ultimately, it just ends up looping back on itself until you accept that SOMETHING is simply the original state.
That is correct, something must be the first cause since an infinite chain of causation is unthinkable.
The origin will always involve self-existence, but self-existence itself is inconceivable (unthinkable).
Regarding the origin, it is easy to see that ALL explanations are inconceivable and literally unthinkable.
This is all detailed in Herbert Spencer's treatise "First Principles". Spencer was agnostic.