So years ago, I was digging around online and found the personal website of whom I believe was a moderately well known SF author.

I thought it might have been Jay Lake or Ted Chiang, but as best I can tell it wasn't either one.

Anyways, the site has several unpublished novellas/novels, and I remember reading one all the way through.

The story began in post-Soviet Union modern era in one of the outlying states, possibly Kazakhstan? The narrator or protagonist comes to see a reputed endless pit in the ground. Said pit is being explored by a team, and he goes with them. They travel downwards for miles, and discover signs of underground life. Eventually it turns out that Nazis remnant forces were still underground, and they fought through, but wind up being trapped and forced to continue downwards.

At that point the story just doubles down, literally, and it starts becoming about a much more ancient civilization in the pit, that predates everyone else. That civilization turns out to be atop an even older one, and it turns out the characters wind up resurrected again as they die, even lower in the pit. Something akin to angels and devils live lower, and the protagonist spends eons fighting them and finally beating their slave-based civilization, before heading even deeper in the pit in hopes of finding bottom.

IIRC, it eventually ends with the protagonist flying a ship a tremendous distance (light years) down the pit before finding a floating pyramid, and then going through a portal..into another endless pit. It ends without ending, as the protagonist decides to carry onwards...potentially forever.

Anyone else ever read this story? It has hints of Greg Bear's The Way universe, but was written with a very different tone. Almost like a shaggy dog story that just keeps growing in scale as you progress. My efforts to find the story again have failed, unfortunately...but it must exist somewhere!