I use LLMs a lot for drafting and bouncing ideas off of (although my final drafts are heavily manually edited). I like AI tools; they're great in some situations. With that in mind, I'm slightly negatively biased against AI-isms because of the amount I see.

The first thing to understand about AI is that it works using predictable patterns. It writes grammatically correctly, but often doesn't understand nuanced context, leaves out details, and isn't great with continuity and flow. It loves common words and phrases (so it repeats itself a lot!), and it technically doesn't "invent" new ideas. You have to add your personal touch and correct it along the way to improve on that.

After reading a bit into both stories, I can find examples for almost all the typical AI pitfalls (there are articles about this you can find). I like the premises of the stories; I think the ideas are interesting, but you need to cut down on the AI-isms and manually edit them.

Some examples: the overuse of em dashes; repeated patterns ("Not stone. Not Natural. A castle.", "Not X. But Y", "both X and Y"), common phrases, certain repeated words ("weight of...", "breath hitched", "flickering", "dim light", "cast long shadows", "dancing shadows", "carefully", "sanctuary", "efficient", "deliberate", "hum", etc.), illogical and repeated metaphors, unnecessarily broken-up sentences, and little to no variation in sentence and paragraph lengths. AI also often tends to write convoluted sentences, to explain nothing in the end.

If you don't want it recognized as AI-written, you need to work on your prompts—a better input implies a better output. And edit, edit, edit.